Stop the Insanity! Physics is Cool Enough Without Excessive Hype!

The Historical Evidence for Excessive Hype in Physics

Bill Clinton Feels My Pain Over Excessive Hype in Physics: imageI attended several seminars on string theory while I was a physics and astrophysics undergrad at the University of Minnesota in the mid 1980’s.  Some of you may recall this was the period in string theory’s history known as the “first superstring revolution.”  In 1984-85, a series of discoveries convinced many theorists that superstring theory (the marriage of string theory and supersymmetry) was going to lead the way to the promised land.  Theoretical physics was essentially complete, I was told.  All that remained was to work out a few details, “tie up some loose ends.” Superstring theory was to be the final theory, the theory of everything from which all other models and predictions could be derived.  It was going to unify all known forces including gravity, and explain all particles and their interactions.  I was told by people whose opinion I assumed was reliable, people whom I thought knew what they were talking about, that “the great discoveries in theoretical physics were over,” capped off by superstring theory. Office Space Parody of String Theory Excesses: imageWell, here we are nearly thirty years later.  String theory has morphed into P-branes and D-branes.  Five different string theories are supposed to be encompassed by M-theory, whatever that is.  You have to accept, without evidence, that supersymmetry is correct and that it is broken in some special way so that the theory remains mathematically consistent yet evades experimental refutation.  Moreover, N=1 supersymmetry was just the start; extended supersymmetry with as many as 8 new supersymmetry transformations is now included in the price of admission.  String theory’s requisite ten dimensions is also unverifiable – the extra six dimensions allegedly compactified in Calabi-Yau manifolds.  And of course, we can’t forget about the 10500 members of the multiverse.  You want some testable predictions and experimental evidence with any of that?  Sorry, that’s an unreasonable expectation for the theory of everything.

So What’s the Harm With a Little Excessive Hype?

String Theory Defined Without the Excessive Hype: image

http://xkcd.com/171/

Young theorists trying to make career decisions have been sold a bill of goods for decades.  Hundreds have chosen to take up string theory because it was supposedly “the only game in town.”  To obtain funding and be competitive for a tenure track job, they were boxed into string theory.  If instead they had been able to follow their own interests and hunches, what sort of foundational discoveries would they have made?  How many physicists who jumped on the string theory band wagon would have made more important contributions in another specialty? I did not become a string theorist 28 years ago.  So why am I still bothered by the deception?  I could excuse this if it only happened once in a while.  But, it has spread throughout theoretical physics and is now de rigueur.  The hype, fluff, and exaggeration is rampant throughout books, documentaries, interviews, and articles.  See, for example, this New York Times article “A Black Hole Mystery Wrapped in a Firewall Paradoxthat threatens the erasure of Einstein’s legacy and of the tremendous successes of the General Theory of Relativity in expanding our understanding and comprehension of the universe.   Additionally, theorists could not resist hyping the multiverse in the new film about the Large Hadron Collider (LHC) and Higgs discovery (Particle Fever), even though the idea generates no testable predictions. Outreach is important.  We want the general public to be interested in fundamental physics so that they will support funding it.  We also want new students to become excited and enthralled so that they will continue the legacy.  But so much of what you see or read is so full of fluff and exaggeration, the reader learns absolutely nothing about physics or the scientific process.  Rather, they just read more silly claims and promises.  And after a while, people that initially had a passing interest in physics become cynical.  Rather than being motivated by the hype, they are turned off by it.  It erodes trust and confidence in those whose ideas and opinions shape the career paths of their students and mentees, as well as the investment of limited tax dollars.

Treating the Excessive Hype Disease

“I feel your pain!” was a popular quote from Bill Clinton.  It likely gained him quite a few votes back in ’92.  We all like to know that other people understand what bothers us, what we are going through.  I find comfort in the fact that more and more physicists are writing books that shine a light on these issues.  An excellent recent book is Jim Baggott’s Farewell to Reality: How Modern Physics Has Betrayed the Search for Scientific Truth. First, he reviews the wonderful progress and discoveries that theoretical physics has made to bring us the truly awesome and inspirational body of knowledge, and modern technologies, that we have today.  Then, he lays out very skillfully the places where theoretical physics has gone off the rails and entered into metaphysics.  These areas include, in his opinion, supersymmetry, grand unification, superstring theory and M-theory, multiverses (in each of its manifestations), the many worlds interpretation of quantum mechanics, and the holographic principle. Several bloggers are also attacking the silliness and excessive hype.  Matt von Hippel has a recent article called “Hype versus Miscommunication, or the Language of Importance.” In it, he takes on a recent Scientific American article called “The Emperor, Darth Vader and the Ultimate Ultimate Theory of Physics.”  Yes, ultimate was used twice in the title, that is not a typo.  Matt offers a more congenial rationalization for this behavior than perhaps I would have, but he may have hit on some accurate insights:

There’s an attitude I often run into among other physicists. The idea is that when hype like this happens, it’s because senior physicists are, at worst, cynically manipulating the press to further their positions or, at best, so naïve that they really see what they’re working on as so important that it deserves hype-y coverage. Occasionally, the blame will instead be put on the journalists, with largely the same ascribed motivations: cynical need for more page views, or naïve acceptance of whatever story they’re handed.  …The problem here is that when you ask a scientist about something they’re excited about, they’re going to tell you why they’re excited about it. …he seems to have tried to convey his enthusiasm with a metaphor that explained how the situation felt to him.

Someone with a casual interest in physics may be drawn to an article with a title as grandiose as “The Emperor, Darth Vader and the Ultimate Ultimate Theory of Physics,” only to be disappointed by the lack of meaningful content.  The article’s author, George Musser, even admits that

The unnerving thing about the theory is that physicists think it exists even though they’ve never written it down and are not even sure they can. …resembles that other creation of the mid-1990s: M-theory, a theory whose existence seems to be implicit in string theory, even though physicists hem and haw when you ask what exactly it is.

Counterproductive and Ineffective Outreach

Is the hype effective outreach?  What are the goals of outreach? If it is to sell more books, increase online readership and documentary viewership, or boost ones ego, then perhaps the hype does support outreach goals.  But if the goals of outreach are to create an educated public who understands the scientific process, understands the limits of our science, understands the available opportunities, who can make informed decisions, and has confidence in our ability to make unbiased recommendations, then I am not so sure that the hype helps achieve these goals. What are the indirect costs in terms of the credibility of science, the misaligned funding priorities, the mismanaged hiring and career opportunities, and so on?  How can we counter pseudoscience like quantum healing or quantum mysticism, when fully credentialed physicists make a living through metaphysics?  If we are willing to compromise the falsifiability requirement, how can we counter fraudulent use of pseudoscience?

Closing Words

When people look back on this era of high energy physics, will they see it as having laid the foundations for new breakthroughs and new discoveries?  Or will they see it as gross mismanagement of resources, talent, and money, while engaged in wild and fanciful goose chases?

Matt von Hippel offers some advice for science writers:

President Kennedy Inspirational Moon Quote image

“We choose to go to the moon in this decade and do the other things. Not because they are easy, but because they are hard.”

We all have to step back and realize that most of the time, science isn’t interesting because of its absolute “importance”. Rather, a puzzle is often interesting simply because it is a puzzle. …they’re hard to figure out, and that’s why we care.  Being honest about this is not going to lose us public backing, or funding. It’s not just scientists who value interesting things because they are challenging. People choose the path of their lives not based on some absolute relevance to the universe at large, but because things make sense in context. You don’t fall in love because the target of your affections is the most perfect person in the universe, you fall in love because they’re someone who can constantly surprise you.”

Three Roads to What Lies Beyond Quantum Mechanics

Alternative Paths to an Interpretation of Quantum Mechanics

Einstein and Bohr discussing Quantum Mechanics image

This is the real reason why we have not been able to discover a theory more fundamental than quantum mechanics. We no longer wear three piece suits to physics conferences.

If you have read my earlier posts, you have likely concluded that I am a realist with respect to the foundations of quantum mechanics (QM).  I believe there is some deeper reality behind the equations of QM.  This deeper reality, or more fundamental theory, will account for the apparent nonlocality that we see in quantum events.  It will also explain the intrinsic randomness in quantum theory, and how nature decides which option to choose.  In my opinion, the wave function (or state vector) represents more than just our knowledge of a system.  However, it may be just an approximation for the correct representation or description of reality.  I also believe that our preconceived notions of reality will need to be altered, just as they were when Einstein developed the Special (SR) and General (GR) Theories of Relativity.

My views contrast with those who believe that QM is the ultimate mathematical formulation.  Among those that believe QM is complete, there are two classes – those that believe it is not even appropriate to ask “why”, “how”, or “what”; and those that seek a set of principles that lead directly to QM.  Members of the first group hold that there is no such thing as objective reality.  Their position is that QM merely encodes what we know (or can not know) about the quantum world.  All we can talk about are the results of measurements that we make.  They argue that it is not even appropriate to ask nature to reveal a deeper understanding, because there is not one.  The second group looks for a deeper understanding, but they look for this conceptual or philosophical foundation within the framework of the current quantum theory.  I think both of these approaches are flawed.  In my opinion, the first approach amounts to forfeiture and the second is a dead end.  To move beyond QM and find a deeper conceptual understanding of the universe, we need to re-zero our preconceived notions and come at the problem from a new direction.

A search of the internet, or YouTube in particular, reveals multitudes of blogs and videos about QM.  There are many high quality documentaries and video clips, with excellent production qualities.  But, the vast majority parrot the ideas that “spooky action at a distance”, entanglement, wave function collapse, the mysterious role of an intelligent observer, etc., are intrinsic magical mysteries of the universe.  They give the impression that our knowledge of the quantum world is secure, and that we might as well accept this bizarre status quo.  Worse, I have seen expert speakers on these documentaries claim that it is not even correct to question these aspects of QM, these are not the “correct questions to ask”.  Metaphysical BS such as “each of us constructs our own version of reality” really gets me going.  No, we are not constructing alternate realities in our heads.  Each of us is constructing a different, flawed and approximated, representation or model of reality in our heads (some more flawed and approximated than others).  But this is not the same as creating a separate reality.  I believe there is some higher level theory, of which QM is an approximation, that will explain these issues.

Quantum Theory as a Labor of Love (Vice Money)

There are several theoretical and experimental physicists doing work on interpretations of QM.  It is hard work.  Generations of physicists have gone before you and have not been able to understand quantum theory.  Additionally, you are working up hill against a field that is only slowly realizing the importance and applicability of your work.  Funding is hard to come by, as you compete with paradigms that have sapped man power and resources for decades.  Frustratingly, you are forced to compete in isolation with these fields despite their lack of actual physics results.  We need more people, and more funding, looking into the foundations and extensions of quantum mechanics.  Back in the 1980’s, many physicists believed that an end run had been found.  They believed that string theory was the theory of everything, from particle physics to cosmology, from the quantum world to black holes.  All the hype has not manifested itself in reality.  It is time to re-tool theoretical physics.  This may mean taking smaller steps, ensuring that we understand where our footing is at each hurdle.

The potential payoffs are huge.  This includes understanding and resolving open issues in Quantum Field Theory, which serves as the basis for the Standard Model of Particle Physics.  It may lead to a theory of quantum gravity, and explanations of dark matter and dark energy.  This would lead to a replacement for the Standard Model of Cosmology (the “Lamda Cold Dark Matter” model – beyond the scope of this post, perhaps more on that later).  These models that aspire to explain all of particle physics and all of cosmology have many free parameters.  The ability to tune these parameters to match the observations weakens our confidence in the uniqueness and correctness of these theories.  Hopefully, a new extension of QM will help fix some of these free parameters.

Getting More Specific About What Lies Beyond Quantum Mechanics

I am not a fan of models that simply add additional mathematical structures to the Schrödinger equation in order to reproduce observed behavior.  Modified Schrodinger dynamics is one example of such attempts.  I am also not a fan of interpretations that ask us to accept too much without conceptual reimbursement, such as the Many Worlds Interpretation (MWI).  In the MWI, each quantum event creates a new universe.  With countless quantum events occurring throughout the universe every moment, the instantaneous proliferation of fully developed universes is staggering, to say the least.

Sean Carroll is a talented and prolific physicist and a wonderful writer. See, for example, his book From Eternity to Here: The Quest for the Ultimate Theory of Time, also linked from my Recommended Reading page.  Dr. Carroll recently gave an interview on interpretations of QM:

I agree with his assessment that the failure of physics to develop a conceptual understanding of quantum mechanics is an embarrassment.  However, I differ with him over his endorsement of the MWI.  There are other interpretations that can resolve the paradoxes of the canonical (Copenhagen) interpretation of QM without such wild assertions and assumptions.  Examples of these alternatives include de Broglie-Bohm mechanics, the Transactional Interpretation, or the Two-State Vector Formalism.  This does not mean that one of these other interpretations are necessarily correct.  It does mean that we should not be so eager and willing to swallow MWI.  The MWI will have to provide a better return on my investment before I start to take it seriously.Many Worlds Interpretation of Quantum Mechanics_image

I have read several papers that attempt to derive quantum mechanics from invariance laws associated with information, probability, causality, contextuality, composability, etc., (name your principle).  While interesting, I just don’t have the sense that these approaches are on track to capture the essence of reality.  Perhaps the problem is that they are starting with the end in mind.  Although “begin with the end in mind” is one of Stephen Covey’s key tenets (The 7 Habits of Highly Effective People), in this case it may be a handicap.

Compare this situation with how Einstein discovered SR and GR.  Einstein was not trying to reproduce Newton’s absolute space and time or Newtonian gravitational theory.  He saw evidence in the world around him and in his thought experiments that led him to postulate a new invariance law.  For SR, it was the constancy of the speed of light.  For GR, it was the equivalence of gravitational and inertial mass.  He then followed these postulates to where ever they took him.  With his new theories, Einstein was able to explain experimental results that contradicted existing theories; the experiment by Michelson and Morley that failed to detect the ether and the anomalous precession of the orbit of Mercury, for examples.  More importantly, he was able to make additional testable predictions.

Stating the Goal: Discovering the Path to What Lies Beyond Quantum Mechanics

So, another approach is to discover some fundamental physical principle(s) that leads to some new theory.  String theory is an example of this.  State a hypothesis: things are made up of strings rather than points.  Then, see where that leads.  However, you have to be willing and able to recognize when your hypothesis is not productive.  Hopefully, the new theory that explains QM will make some testable predictions that contradict other interpretations of conventional QM, so that we can tell which is right and which is wrong.  As if that would not be awesome enough, an even more amazing discovery would be a theory that reduces to QM in one limit, and GR in another.

I want to stress that I think this more fundamental theory will likely be founded on principles that seem, at first blush, to not have much to do with classical QM or GR.  And the math may look very different until approximations are made.  There may be additional hidden variables that are not accounted for in the current set of equations.  Something totally new.  Extra dimensions perhaps.  Not necessarily extra space or time dimensions.  But, some extra freedom for the “force carriers”, for entanglement, or for whatever advanced and retarded wave functions are representing.

Maybe some applicable insights can be found in the Aharanov-Bohm effect, Significance of Electromagnetic Potentials in the Quantum Theory.  Aharanov and Bohm showed that, contrary to classical mechanics and classical electromagnetism, the electromagnetic four-potential can have an observable effect on charged particles, even in regions where the electric and magnetic fields cancel (where there are no forces on the particle).

Fields such as a gravitational field, an electric field, or a magnetic field can be described in terms of a potential.  In the case of electromagnetism, you need a scalar and a vector potential.  Gravitational fields require a tensor potential.  The fields can be derived from the potentials.  However, the potentials can not be uniquely determined from the fields.  That is getting more in depth than we should for the present.  Suffice it to say, however, that prior to the prediction (and subsequent experimental verification) of the Aharanov-Bohm effect, physicists believed that all physically relevant dynamics could be expressed in terms of the fields.

In the Aharanov-Bohm effect, an electrically charged particle is affected by an electromagnetic field despite being confined to a region in which both the magnetic field and electric field are zero. This is an apparent nonlocality of the field interactions.  However, it can also be interpreted as the coupling of the electromagnetic four-potential with the phase of a charged particle’s wave function.  The effect is observed in interference experiments, where the phase difference of two interfering wave functions (state vectors) modifies the interference pattern.  The Aharonov–Bohm effect shows that the electric and magnetic fields do not contain full information about the physics.  The electromagnetic four-potential offers a more complete description of electromagnetism than the electric and magnetic fields alone can.

Seeing Only the Shadows of the Quantum Universe

Like the prisoners in Plato’s Allegory of the Cave, what we see taking place at the quantum level may be just shadows of the true reality.

The title of this post, “Three Roads to What Lies Beyond Quantum Mechanics”, is a play on the title of Lee Smolin’s quantum gravity book: Three Roads To Quantum Gravity (Science Masters).
 

The Transactional Interpretation of Quantum Mechanics

What is so strange about the Transactional Interpretation?

Transactional Interpretation: No stranger than the Multiverse in String Theory imageThousands of physicists are willing to give serious consideration to the notions that the universe contains eleven dimensions, and that there may be something like 10500 universes in the multiverse.  They have been willing to dedicate their careers over the past three or four decades to the study of string theory, despite the lack of experimental support.  So, why are not more physicists willing to take the idea of advanced wave functions more seriously?  What’s wrong with a little backwards time-travel?  After all, that’s what led Dirac, mathematically, to predict antimatter.  We need more physicists exploring the implications of models like the Transactional Interpretation of Quantum Mechanics (TIQM), and trying to develop ideas for testing such alternative explanations for the bizarre and unintuitive behavior of matter on the quantum level.

What is the Transactional Interpretation of Quantum Mechanics?

The wave function is the quintessential component of mathematical descriptions of the quantum world.  It describes the state of a quantum system and the Schrödinger equation describes how the wave function evolves in space and time.  The Schrödinger equation is not relativistically invariant.  However, relativistically invariant equations have been developed; the Klein-Gordon equation and the Dirac equation, for examples.  The solution to these equations that moves forward in time is known as the retarded wave.  Consistent with our common-sense notions of time, this is the one that is assumed to be physically relevant.  But the complex conjugate of a retarded wave is also a solution.  This wave travels backwards in time and is called an advanced wave.  Normally, this advanced wave solution is ignored.

Physicist John Cramer proposed TIQM back in 1986. The TIQM makes use of both the retarded and the advanced waves.  Using the mathematical formality of TIQM, you can calculate and predict the outcomes of the same experimental and natural situations as conventional QM.  And, you arrive at identical quantitative results.  The bonus with the TIQM is that you also get a comprehensible explanation for what physically is going on.  And, you avoid the assumptions, add-ons, and paradoxes, inherent to the canonical interpretation.  TIQM provides an explanation for how nature produces bizarre results in some experiments, results that are consistent with the mathematics of QM but that seem to defy our conceptions of space and time.

Application of the Transactional Interpretation

Transactional Interpretation: Physicists and their sense of humor imageIn one of my earlier posts, Quantum Weirdness: The unbridled ability of quantum physics to shock us, I discussed interaction-free and delayed choice experiments.  TIQM provides a conceptual and physical description of what the universe is up to in these experiments; how it pulls off these seemingly bizarre results.  Quantum interactions are described in terms of a standing wave formed by retarded and advanced waves.  Events require a “handshake” between the emitter and the absorber, a handshake through space and time. This is an explicitly nonlocal model for quantum events.  Nonlocality means that in quantum mechanical systems “relationships or correlations not possible through simple memory are somehow being enforced faster-than-light across space and time.”

Advantages of TIQM over mainstream alternatives include (from Cramer’s A Transactional Analysis of Interaction Free Measurements):

  • it is actually already present in the mathematical formalism of quantum mechanics
  • it is economical, involving fewer independent assumptions
  • it is paradox-free, resolving all of the paradoxes and counter-intuitive aspects of standard quantum theory, including nonlocality and wave function collapse
  • it does not give a privileged role to observers or measurements
  • it permits the visualization of quantum events

In TIQM, a source emits the usual (retarded) wave forward in time.  It also emits an advanced wave backward in time.  A receiver emits an advanced wave backward in time and a retarded wave forward in time.  A transaction is accomplished in three stages: (1) An offer wave (the usual retarded wave function) originates from the source and spreads through space-time until it encounters the absorber.  (2) The absorber responds by producing an advanced confirmation wave (the complex conjugate wave function), which travels in the reverse time direction back to the source. (3) The source chooses between all possible transactions based on the strengths of the echoes it receives.  Then, the potential quantum event becomes reality.  A probability can be calculated for each viable outcome using the wave function amplitudes, in the same manner as the Born rule in conventional interpretations.  The phases of the offer and confirmation waves are such that the retarded wave emitted by the receiver cancels the retarded wave emitted by the sender.  The advanced wave emitted by the receiver cancels the advanced wave emitted by the sender.  Hence, there is no net wave after the absorption point or before the emitting point.

Transaction Interpretation explains interaction free measurements and delayed choice experiments

Transactional Interpretation of Quantum Mechanics and Interaction Free Measurements: Mach-Zehnder open paths imageConsider a Mach-Zehnder interferometer, such as the device discussed in my earlier post (Quantum Weirdness: The unbridled ability of quantum physics to shock us).  A Mach–Zehnder interferometer is used to measure the relative phase shift differences between two collimated photon beams.  The beams are created by splitting light from a single source.  These two figures of a Mach-Zehnder interferometer, and the summary that follows, are from Cramer’s A Transactional Analysis of Interaction Free Measurements.  Please see that reference for a more detailed description and quantitative discussion.  Although Cramer’s paper specifically addresses an experiment with interaction free measurements, similar arguments and calculations apply to delayed choice and quantum eraser experiments.Transactional Interpretation of Quantum Mechanics and Interaction Free Measurements: Mach-Zehnder blocked path image

In a Mach-Zehnder interferometer, light from source L goes to a 50%-50% beam splitter S1 that divides incoming light into two possible paths. These beams are deflected by mirrors A and B, so that they meet at a second beam splitter S2 which recombines them by another reflection or transmission. The combined beams then go to the photon detectors D1 and D2.  Light source L emits only one photon within a given time period.  If paths A and B have identical lengths, the superimposed waves from the two paths are in phase at D1 and out of phase at D2. This is because with beam splitters, a reflected wave is always 90 degrees out of phase with the corresponding transmitted wave. The result is that all photons from light source L will go to (be observed at) D1 and none will be observed at D2.  Walk through the figures and make sure you understand why this is so before proceeding.

Next, use an opaque object to block the lower path (path A). It will insure that all of the light arriving at beam splitter S2 has traveled by path B. In this case there is no interference, and the 50%-50% beam splitter S2 sends equal components of the incident wave into both detectors.  Hence, there is equal probability to observe a photon in either detector.  This is a subtle and important point.  With both paths open, the waves arriving at D2 interfere destructively while the waves arriving at D1 interfere constructively.  Hence no photons are observed at D2.  When path A is blocked, there is no additional wave to interfere with the wave from path B, which is split and sent to both detectors.

Quantitative Application of the Transactional Interpretation

To put some numbers behind this, we can actually calculate the amplitudes of the individual waves.  In the end, we find that TIQM is numerically equivalent to the predictions of conventional QM methodologies.  The difference is in how you interpret (or explain) what the universe is doing and why you calculate it in a particular way.  In TIQM, you account for the effects of splitting, reflecting, transmitting, combining, interfering, etc., on the amplitude and phase of each offer wave and confirmation wave. You then arrive at the following quantitative predictions.  If there is no blockage on path A, we will detect the photon at D1 100% of the time.  If we perform the same measurement with path A blocked, we will detect a photon at D1 25% of the time, a photon at D2 25% of the time, and no photon at all 50% of the time (because it is absorbed by the object in path A).  “…the detection of a photon at D2 guarantees that an opaque object is blocking path A, although no photon has actually interacted with object”.

Consider again the situation in which no object is present in path A. The offer waves from L to detector D1 arrive at D1 with the same amplitudes and in phase with each other.  They interfere constructively, reinforce, and produce a confirmation wave that is initially of amplitude 1.  This confirmation wave then returns to the source by all available paths. Each path brings the confirmation wave to the source L in phase because, as with the offer waves, the confirmation waves on both paths have been transmitted once and reflected twice.  Similarly, the offer waves from L to detector D2 arrive at D2 180 degrees out of phase, because the offer wave on path A has been reflected three times while the offer wave on path B has been transmitted twice and reflected once. Therefore, the two offer waves interfere destructively and cancel at D2, and no confirmation wave is produced as a result.  Since the source L receives a unit amplitude confirmation wave from detector D1 and no confirmation wave from detector D2, the transaction forms from L to D1 via paths A and B. The result of the transaction is that a photon is always transferred from the source L to detector D1 and that no photons are transferred to D2.

When there is an object blocking path A, it is probed both by the offer wave from L and by the aborted confirmation waves from D1 and D2.  When a photon is detected at D1, the object has not interacted with a photon. However, it has been probed by offer and confirmation waves from both sides, modifying the interference relationship at the detectors, and hence the ultimate probabilities. The offer wave along path A never reaches one of the detectors (but it does reach the object). The offer wave on path B reaches both detectors.  The source receives confirmation waves from both detectors (returning along path B) and also from the object.  This leads to the probabilities mentioned above.

Transactional Interpretation: Conclusions

Transactional Interpretation: Time Paradox imageIn the TIQM, interactions are explicitly nonlocal because “the future is, in a limited way, affecting the past (at the level of enforcing correlations)”.  One of the consequences of the TIQM is that it forces us to alter our understanding of essentially all interactions or observations:

“When we stand in the dark and look at a star a hundred light years away, not only have the retarded light waves from the star been traveling for a hundred years to reach our eyes, but the advanced waves generated by absorption processes within our eyes have reached a hundred years into the past, completing the transaction that permitted the star to shine in our direction.”

TIQM offers to resolve many of the paradoxes inherent in QM, such as the mystery of wave function collapse and the awkward role of the observer.  However, it does not specifically answer the question what is the wave function; what is waving.  It also requires you to accept the physicality of advanced waves travelling backwards in time.  To me, there seems to be something important in these ideas.  Something pointing towards a more fundamental theory of the quantum world.  I appreciate the fact that it seeks to offer an explanation.  Additionally, it does not seem to carry as much intellectual or conceptual baggage as some other alternative interpretations (more on this in future posts).

For more information, see John Cramer’s TIQM webpage: The Transactional Interpretation of Quantum Mechanics,  or An Overview of the Transactional Interpretation.   Selected publications by John Cramer can be found here: Research in Theoretical Physics.

Fun with Quantum Computing at University of Bristol

Physics is Fun, at University of Bristol

Run your own quantum computing experiments

Quantum Computing at University of Bristol imageHave fun with quantum physics and quantum computing!  Gain practical experience using the resources offered by University of Bristol: Qcloud.  Test out your quantum experiments in their online quantum processor simulator; includes reference material and users guide.  Then, you can (starting 20 September) register and run your experiment in their lab: “create and manipulate your own qubits and measure the quantum phenomena of superposition and entanglement.

 

Quantum Weirdness: The unbridled ability of quantum physics to shock us

Double slit experiments and the root of quantum weirdness

Quantum weirdenss: quantum superposition meets life cartoon

You are probably familiar with the legendary double slit experiment.  It is a simple, straight-forward experiment that introduces the wave-particle duality and the weirdness that is at the foundation of quantum mechanics.  Many people read or hear about the generic double slit experiment and assume that it is the end of the story.  Worse, many intrinsically curious people erroneously assume that this phenomenon is understood.  Or, they believe that they have a benign explanation for a particular experimental result.  Hence, they don’t dig deeper into the challenge and excitement that can be found in the quantum world.  Digging through the layers of experimental results helps ensure we are questioning the implications of our hypothesis, and testing whether it remains consistent and valid.

In the typical double slit experiment, a beam of light is directed at a pair of slits in a wall.  The resultant interference pattern is then observed on a screen or some other sort of detector.  You can see a five-minute introduction to the double slit experiment by Dr. Quantum: “Double Slit Experiment”.  Photons are typically used, although according to de Broglie and confirmed by Davisson and Germer, electrons or any other particle will work.  Using photons greatly simplifies the technical difficulties and cost of the experiment.

Quantum Weirdness: double slit interference pattern imageThe experimental apparatus consists of a coherent light source, a wall with two narrow slits (the width and separation of the slits are comparable to the wavelength of the light), and a detection screen behind the wall.  A narrow beam of light strikes the pair of slits.  The pattern on the detection screen is an interference pattern.  So what, light is a wave.  Or, at least it acts that way sometimes.  We can easily calculate the details of the interference pattern using the dimensions of the experimental setup and the frequency of the light.  The two different paths, (source – slit A – screen; or source – slit B – screen), have different path lengths.  Hence, the two interfering waves have different phases and can add constructively or destructively.

Doubling the dosage of quantum weirdness

The rub comes in when you dial down the intensity of the beam of light so that only one photon at a time is passing through the slits.  One photon can’t pass through both slits, right?  It can’t interfere with itself, right?  Well, the interference pattern is still there.  Quantum mechanics tells us that the photon is in a superposition of states.  See Feynman’s QED: The Strange Theory of Light and Matter (Princeton Science Library) or Cox and Forshaw’s The Quantum Universe: (And Why Anything That Can Happen, Does)for excellent conceptual descriptions of how to visualize what the particle is up to.

Quantum Weirdness: Wave-Particle Identity Crisis image

I can contemplate how a single “particle” can act like a wave sometimes, a particle other times, or some combination thereof.  I can do that without feeling like I am losing my grip on reality.  But, here is where things start to get really weird.  If you modify the above experiment so that you can tell which slit the photon traveled through, the interference pattern goes away.  It is as if each photon realizes they are being watched and stops their shenanigans.  But how do they “know” they are being watched?  How do they know that it is time for wave function collapse”?  In wave function collapse, the photon discards the superposition of states and selects a specific value or path (a specific eigenstate).

The quantum measurement problem

This is the crux of the quantum measurement problem:   Why are there two different processes describing the evolution of a particle’s wave function?  These two processes are (1) the continuous evolution described by Schrödinger’s equation, and (2) the spontaneous collapse into a specific eigenstate.  What triggers the collapse?  Why can’t we observe a superposition or the collapse process? How can a wave function that is spread out over arbitrary distances collapse seemingly instantaneously?  Some scientists have argued that wave function collapse is triggered by an interaction between the observer and the photon, or between the measurement apparatus and the photon.  For example, the momentum that is imparted to the photon by the act of measurement may break the superposition. The problem with this argument, however, is that clever experimentalists have already devised and carried out experiments using interaction-free measurements.

Now for some truly bizarre quantum weirdness

If you have followed the discussion so far, it is still not safe to unfasten your seatbelt and start walking about the cabin.  This is the point where I start to feel my grip on reality slipping away.  Particles are doing something we completely do not understand, in apparent response to some trigger we completely do not understand.  Consider delayed choice experiments and quantum eraser experiments.  In delayed choice experiments, the decision to determine which path the photon used is made well after the photon has passed the slits*.  Yet, the results seem to indicate that the photon has retroactively collapsed its wave function and chosen a single path.  If you mark through which slit each photon went, the interference pattern is destroyed.  This happens even if you mark the path without disturbing the photons movement.  In quantum eraser experiments, photons are tagged based on which path they took. By itself, that tagging destroys the interference pattern.  However, when this path information is discarded (erased), the interference pattern is restored.

This begs the following questions: What happens to the discarded part of the wave function when wave function collapse occurs?  Some people argue that the wave function is not real, it just encodes our knowledge of the situation.  But when the tagging is erased, how does the quantum system “know” what superposition to re-enter?

Quantum Weirdness: delayed choice quantum eraser experiment imageDelayed choice quantum eraser” experiments combine all of the absurdities of the above experiments.  This experiment is arranged to identify which one of the paths the photon uses.  And, this information can be erased after the fact.  See the adjacent figure from Wikipedia.  Photons are emitted one at a time from the lower-left and then subjected to a 50% beam splitter.  After the beam splitter (green block), photons travel along two possible paths, the red or blue lines. Reminds me of a Tokyo subway map.  In the top diagram, the trajectory of each photon is known. If a photon emerges at the top of the apparatus, it appears to have come by the blue path.  If it emerges at the side of the apparatus, it appears to have come by the red path.  As shown in the bottom diagram, a second beam splitter is introduced at the top right.  This can direct either beam towards either path, erasing the which-path information.  So, the decision whether or not to remove the path information is made after-the-fact.  If you remove the path information, the interference pattern is restored.  The photon appears to recover its superposition properties.

Mind-blowing quantum paradoxes

Indeed, quantum physics is rich with paradoxes and non-intuitive behaviors.  While contemplating a certain experiment, it is important to ensure you have a complete picture of what the theorists and experimentalists are trying to tell us.  By merely considering one particular experiment, it is possible to convince yourself that you understand what is happening.  But, other experiments may contradict or invalidate your conceptual line of reasoning.  It seems to me that there is some deep, underlying concept or unifying principle that we are missing.  Some key piece of the puzzle that will show us that superposition and entanglement are fundamental, and apparently not constrained by space and time.  There must be some (comprehensible) reason for why matter behaves like this.

* Many experiments use alternative path-separation devices, such as mirrors or beam splitters.  Additionally, different techniques have been used to “tag” specific paths or to detect the photons.  The math and the concepts are the same in these various setups.  Different arrangements help to clarify the results and resolve concerns over subtle technical issues.
 
Einstein quote image"The supreme task of the physicist is to arrive at those universal
elementary laws from which the cosmos can be built up by pure
deduction. There is no logical path to these laws; only intuition,
resting on sympathetic understanding of experience, can reach
them."
				- Albert Einstein

 

Contrary to Popular Belief, Einstein Was Not Mistaken About Quantum Mechanics

Misconceptions and assumptions concerning quantum mechanics

I get somewhat frustrated every time I read another blog post, book review, or journal article that claims Einstein was wrong about quantum mechanics (QM).  It must make for good headlines and is almost cliché.  First, these articles often give the misleading Einstein and quantum mechanics imageimpression that Einstein was the only physicist who had concerns with quantum mechanics during its development and exposition.  That simply is not true.  Many physicists (Schrödinger, de Broglie, Podolsky, Rosen, and several other major figures) had concerns.  Additionally, the relatively small fraction of physicists that are active today in the foundations and interpretations of quantum mechanics continue to debate the meaning, the implications, and the completeness of the theory with great vigor.  There is not yet a general consensus among experts as to the answers to some of the most fundamental questions about the implications of quantum theory in its present form.

For decades, there has been a common misconception among many physicists that the conceptual problems with QM were already resolved or that any remaining questions were purely philosophical.  Contributing to this state of affairs, many textbooks focused solely on the computational aspects.  If interpretations or foundations were discussed at all, the focal point was on the Copenhagen interpretation.  There was little or no discussion of other viable formulations, and the solutions to conceptual problems that these formulations offered.  The prevailing interpretation of QM does not give a clear answer to the question “what, if anything, is objective reality”. Some alternatives, such as de Broglie-Bohm mechanics, do.  According to de Broglie-Bohm mechanics, particles are objective point-like objects with deterministic trajectories. These trajectories are guided by wave functions, which also objectively exist.

Alternatives to conventional quantum mechanics

I am not at all claiming that de Broglie-Bohm mechanics in its current form is the final word.  And I am not claiming that we need to immediately replace our existing paradigm with it, without further consideration or modification.  However, de Broglie-Bohm mechanics has not been properly vetted by generations of physicists.  I think failure to fully consider and evaluate such approaches may be blinding us to the way ahead.  The prevailing, fractured conceptual understanding of QM may be holding us back from making the next theoretical and technical leap in our quest to understand the universe.

The venerable John S. Bell had this to say about de Broglie’s wave theory (see Speakable and Unspeakable in Quantum Mechanics):

“Is it not clear from the smallness of the scintillation on the screen that we have to do with a particle? And is it not clear, from the diffraction and interference patterns, that the motion of the particle is directed by a wave? De Broglie showed in detail how the motion of a particle, passing through just one of two holes in screen, could be influenced by waves propagating through both holes. And so influenced that the particle does not go where the waves cancel out, but is attracted to where they cooperate. This idea seems to me so natural and simple, to resolve the wave-particle dilemma in such a clear and ordinary way, that it is a great mystery to me that it was so generally ignored”

 And this about Bohmian mechanics:

 “In 1952 I saw the impossible done. It was in papers by David Bohm. Bohm showed explicitly how parameters could indeed be introduced, into nonrelativistic wave mechanics, with the help of which the indeterministic description could be transformed into a deterministic one. More importantly, in my opinion, the subjectivity of the orthodox version, the necessary reference to the “observer,” could be eliminated. … But why then had Born not told me of this “pilot wave”? If only to point out what was wrong with it? … Why is the pilot wave picture ignored in text books? Should it not be taught, not as the only way, but as an antidote to the prevailing complacency? To show us that vagueness, subjectivity, and indeterminism, are not forced on us by experimental facts, but by deliberate theoretical choice?”

EPR and quantum entanglement

The famous “EPR paper”, so-named due to its authorship: A. Einstein, B. Podolsky, and N. Rosen, “Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?”, laid out some of Einstein’s main concerns.  These included lack of an objective physical reality in which deterministic properties of observables exist regardless of measurement.  And nonlocality, in which a measurement process carried out on one of a pair of entangled particles can seemingly affect the other particle’s properties, instantaneously and without regard to distance.Real-world quantum entanglement cartoon  Einstein continued to voice his objection to this fundamental property of quantum mechanics: “because it cannot be reconciled with the idea that physics should represent a reality in time and space, free from spooky actions at a distance.”  (Max Born, ed., The Born-Einstein Letters: Friendship, Politics and Physics in Uncertain Times (Macmillan, 1971), p. 178).

After Einstein’s death, the phenomenal John Bell figured out how to quantify the “spooky” part of the intrinsically probabilistic behavior of a pair of entangled particles.  See his papers in Speakable and Unspeakble in Quantum Mechanics.  Years later, experimentalists such as Freedman, Clauser, and Aspect, confirmed that Nature really does make use of this spooky action at a distance, or nonlocality.  But to what end?

Although nonlocality has subsequently been confirmed experimentally, it is ludicrous to criticize Einstein for his concerns about a theory that included it.  It would be a sad day for science if such a huge paradigm shift swept over the community without raising a few hairs.  Additionally, physicists still do not understand how the nonlocality is achieved, nor its implications.

The quantum measurement problem

A related issue is wave function collapse and the “measurement” problem. The measurement problem manifests itself in the fact that there are two rules for how a quantum state evolves in time. The Schrödinger equation tells us how the wave function (or more generally, the state vector) evolves in time when a quantum system is not being “observed” or “measured”.  With the Schrödinger equation, you can calculate the probabilities for possible outcomes to different measurements, and how those probabilities change over time.  This evolution of the state vector while no one is looking is continuous.  However, instantaneous collapse of the state vector into a particular eigenstate occurs upon measurement.  Why the discontinuity in the descriptions of the two processes?  What constitutes a measurement?  What are the dynamics for wave function collapse?  Does this mean that wave functions (or state vectors) are approximations to some more complete description of quantum systems?

The Dalek Interpretation of Quantum Mechanics cartoonThe collapse postulate is ad hoc, based on the fact that we never observe superpositions of quantum states.  The core of the measurement problem is the inability of QM to explain the abrupt transition from linear evolution of the wave function, to non-unitary wave function collapse.  Steven Weinberg summarizes it thusly: “during measurement the state vector of the microscopic system collapses in a probabilistic way to one of a number of classical states, in a way that is unexplained and cannot be described by the time-dependent Schrödinger equation.”

Conclusions

So, objective reality is not understood, nonlocality is not understood, wave function collapse is not understood.  We could go on.  My impression, based on trends in the literature, is that more and more of the community of physicists is recognizing the holes that remain in our conceptual understanding of the quantum world.  As more and more theoretical and experimental physicists struggle with these issues, perhaps we will get closer to a breakthrough.

Additional material

Here is a YouTube video with a quick introduction to entanglement: Quantum Entanglement – The Weirdness Of Quantum Mechanics.  And a ScienceDaily article on quantum entanglement, including links to additional background information on quantum mechanics.

Comrade on the quest

To my delight, just as I finished writing and editing this post, I found the following article on the electronic preprint archive, arXiv.org.  Submitted today by Pablo Echenique-Robba, who apparently shares many of my views on the current state of QM:

Title: Shut up and let me think! Or why you should work on the foundations of quantum mechanics as much as you please.

 Abstract: If you have a restless intellect, it is very likely that you have played at some point with the idea of investigating the meaning and conceptual foundations of quantum mechanics. It is also probable (albeit not certain) that your intentions have been stopped on their tracks by an encounter with some version of the “Shut up and calculate!” command. You may have heard that everything is already understood. That understanding is not your job. Or, if it is, it is either impossible or very difficult. Maybe somebody explained to you that physics is concerned with “hows” and not with “whys”; that whys are the business of “philosophy” — you know, that dirty word. That what you call “understanding” is just being Newtonian; which of course you cannot ask quantum mechanics to be. Perhaps they also complemented these useful advices with some norms: The important thing a theory must do is predict; a theory must only talk about measurable quantities. It may also be the case that you almost asked “OK, and why is that?”, but you finally bit your tongue. If you persisted in your intentions and the debate got a little heated up, it is even possible that it was suggested that you suffered of some type of moral or epistemic weakness that tend to disappear as you grow up. Maybe you received some job advice such as “Don’t work in that if you ever want to own a house”.   I have certainly met all these objections in my short career, and I think that they are all just wrong. In this somewhat personal document, I try to defend that making sense of quantum mechanics is an exciting, challenging, important and open scientific endeavor. I do this by compulsively quoting Feynman (and others), and I provide some arguments that you might want to use the next time you confront the mentioned “opinions”. By analogy with the anti-rationalistic Copenhagen command, all the arguments are subsumed in a standard answer to it: “Shut up and let me think!”

 

The Folly of Physics: Interpretations of Quantum Physics, Part 1

The issue

With this post, I begin to layout some concerns that I have with descriptions and interpretations of quantum physics.  We still do not have a conceptual understanding of what the heck is going on in quantum mechanical processes.  Albert Einstein took issue with several aspects of quantum theory: the inherent randomness, the nonlocality, and the lack of realism, for example.  We may need to accept these aspects of nature, but is it asking too much to be able to understand how/why/what the universe is doing in these situations?

Quantum physics is a fickle mistress

Quantum Mechanics (QM) is perhaps one of the most successful hypotheses in the history of physics. That is, if you evaluate success based on agreement with experiment and ability to make predictions that are later confirmed by experiment.  And, quite frankly, that is (quite appropriately) how science judges hypotheses and theories.  Thousands of experiments have been performed, verifying the accuracy and relevance of QM.  These experiments include emission or absorption spectra predictions and measurements, magnetic moment predictions and measurements, and multiple variations of the double slit experiment, to name a few.  Physicists, chemists, and engineers have subjected matter to all kinds of bizarre tests that have validated the theory’s un-intuitive predictions.  Additionally, QM is not just a theoretical curiosity.  The range of technologies based on it is staggering.  Without QM, we would not have PCs, iPads, smart phones, laptops, modern TVs, modern medical imaging equipment, the microchips that control everything from our cars to our refrigerators, and so on.

Unexplained behavior in quantum physics experiments. imageYet, after all this, we still do not understand HOW quantum physics works.  Even though the theory is a century old, we are far from a proper conceptual understanding of what it actually means and HOW the universe pulls off this behavior.  How does a particle manage to take every possible path?  How does a wave function seem to collapse, essentially instantaneously, across arbitrary distances?  How do entangled particles influence each other, seemingly without regard to time and space?  Why do certain quantities have to be quantized, rather than continuous?  These difficulties are related to the fact that a complex-valued state vector is used to describe a physical system.  So another way to ask these questions is, “why are complex quantities and a state vector required to quantitatively describe behavior at the quantum level?”

Why is it so hard to visualize quantum physics?

We can visualize general relativity (GR).  It is understood as the interplay between matter and spacetime.  Apart from some warping and dilation, GR makes intuitive sense.  There is a speed limit and strict enforcement of locality.  With some mathematics, we can readily convince ourselves that causality is safe.  Electromagnetic and nuclear interactions are described mathematically and conceptually as due to the exchange of particles called bosons.  These particles (photons for electromagnetism, gluons for the strong nuclear force, W and Z bosons for the weak nuclear force) account for the transfer of momentum and energy between fermions (i.e. quarks, electrons, protons, etc.).  They also account for the transfer of conserved quantum numbers.  In none of these fundamental forces do we have “spooky action at a distance”, or nonlocality.  We do have virtual particles, which is another story and takes some time to get used to.  But at least, even then, we have a picture in our heads of what is going on.

In quantum physics, the state vector is not a physical description of the system.  And the evolution of the state vector seems to occur in two distinct phases.  First, a continuous evolution of the state vector occurs as the system evolves in time and space (described, for example, by the Schröedinger equation).  Then, there is an abrupt and discontinuous collapse of the state vector, into a particular eigenstate; the dynamics of which are not understood.  A common misconception is that this state vector collapse is caused by the interaction with the measurement device.  But clever, interaction-free measurement processes have been devised.  The collapse of the wave function has been verified in situations where interactions play no role in the measurement.  At least no known interactions.

Why should we care about conceptualizing quantum physics?

Given that QM works so well, and (so far) no experiments have contradicted it, why should we care how it is interpreted?  QM does not provide a physical description of a process.  The old adage is to just “shut up and calculate” (David Mermin).  However, this lack of a conceptual understanding may be what is holding physicists back from uniting the two pillars of modern physics, QM and GR.  It may be the key to understanding many of the most fundamental and provocative questions physicists are struggling with:

  • How do we unite the two theoretical paradigms of modern physics, QM and GR?
  • What happened at (and before) the origin of the universe?
  • What will be the ultimate fate of the universe?
  • What is driving the apparent acceleration of the universe’s expansion (i.e. what is dark energy)?
  • What happens inside a black hole?
  • What is time?

It may also be necessary for the next great leap in technology, such as quantum computing.  Besides all that, I just want to know.  Is that asking too much?

Competing interpretations of quantum physics

At least to some extent, I think QM has been a victim of its own success.  Since it has worked so well, there is little less motivation to fix it.  Additionally, it is very difficult to distinguish between the predictions of some of these different interpretations.  So it will be difficult to experimentally validate the correct interpretation, at least for some time.

Many different interpretations have been offered up over the years.  I will dig into some of these in later posts.  To name a few (Frank Laloë, “Do We Really Understand Quantum Mechanics?”):

  • Statistical interpretation
  • Relational interpretation
  • Logical, or algebraic approach
  • Veiled reality
  • Additional (hidden) variables
  • Modified Schröedinger dynamics
  • Transactional interpretation
  • History interpretation
  • Everett interpretation
  • Modal interpretation

One of my favorites is the de Broglie-Bohm pilot wave interpretation.  In this model, a particle’s motion is determined by a wave.  Hence, you can reproduce both particle and wave-like behaviors and the predictions of generic QM.  However, there are some issues with de Broglie-Bohm theory.  These include things like relativistic invariance and the dynamics for how the particle and wave influence each other.  “We’ll talk about that later”.

Unfortunately, alternative explanations have not been given full and proper consideration over the past 86 years (since the 1927 Solvay Conference and the birth of the Copenhagen interpretation).  Some alternatives have been appropriately disproven.  However, others have just been over-ridden or ignored.  A common theme is that someone publishes a paper “showing” that some interpretation is not workable.  Later, someone else shows how that paper was in error.  People remember the first paper and continue to assume that a certain idea is untenable.  Various interpretations are confused with each other, or assumptions are confused with conclusions.  Scientists are erroneously lead to believe that a particular approach is not valid.

These myths are perpetuated in text books and lectures.  One example is de Broglie’s hidden variables theory, which was relegated to the scrap heap after the 1927 Solvay Conference.  It was resurrected after David Bohm developed his theory in the 1950s, and the similarities between it and de Broglie’s earlier work were noticed.  Another example: experiments confirming the violation of Bell’s inequality and hence confirming the concerns of the famous EPR paper (Einstein, Podolsky, Rosen) are often cited as confirming hidden variables theories are unworkable.  They actually show that hidden variables theories cannot sidestep the apparent nonlocality, not that they are altogether un-viable.

De Broglie-Bohm mechanics at work?

Take a look at this amazing video from the Science Channel’s Through the Wormhole, on Wave/Particle dynamics with silicon droplets.  It shows how the results of the double slit experiment can be reproduced by a silicon droplet (the “particle”) riding on an actual, physical “wave”.  There are a lot of details that go into this experiment, including how the apparatus works and how it is filmed.  So it is definitely not a proof of de Broglie-Bohm mechanics.  However, it is intriguing, and offers an irresistible visualization that begs further investigation.

I think a significant factor in our failure to develop a consistent and deep conceptual understanding of quantum physics is rooted in the dogmatic presentation of the prevailing interpretation.  For decades, up-and-coming physicists have been indoctrinated in the “Copenhagen interpretation”.  Presented with the implicit assumption that interpretation questions are settled, many students don’t dig deeper.   The development of a proper, conceptual understanding has been further hobbled by misconceptions that are perpetuated through textbooks and instructors.  Students either assume the issue is resolved and look elsewhere for research opportunities, or they are discouraged by their advisors and forced to conform to availability of funding and job opportunities.

I recall being confused and frustrated, as an undergrad physics student, when the explanations in the textbook or provided by the professor, just did not make sense and did not seem to be consistent with what the mathematics implied.  For example, the meaning and implication of the uncertainty principle are often explained as being due to the unavoidable transfer of momentum to the observed particle during a measurement.  However, experiments have been done that show this is not the case.  Moreover, it is an intrinsic property of the mathematics, in which momentum and position are Fourier transformations of each other, like time and frequency in everyday applications of Fourier theory to acoustic or electromagnetic signals.

Conclusion

In the weeks and months ahead, I will expand on the specific points brought up in this article. It is entirely possible that Nature really is unknowable.  The Universe probably does not feel compelled to satisfy my desire for a visual, comprehensible model, unless it already intended to do that anyway.

MiniBooNE to search for Dark Matter!

Good news! MiniBooNE will be searching for dark matter!  I am involved in a neutrino experiment at Fermilab called MiniBooNE.  For several years now, we have been measuring neutrino and anti-neutrino cross-sections, and searching for exotic neutrino oscillation signals.  But now, instead of making and studying neutrinos, we are going to run in a different mode and see if we are making dark matter in our beamline.

MiniBooNE Detector Tank imageThe MiniBooNE detector studies neutrinos produced in Fermilab’s Booster Neutrino Beamline.  Protons accelerated in the Linac and Booster strike a Beryllium target, producing a bunch of pions and occasionally kaons.  The target is inside a magnetic horn which focuses these charged mesons into a beam.  The pions and kaons travel along a 50 meter tunnel and decay, producing neutrinos.  Some of the neutrinos then interact in MiniBooNE, which is filled with mineral oil, and about 500 meters from the target.

For the dark matter search, we want to minimize the neutrino production to minimize the number of neutrino interactions in the detector, which are a background for the dark matter search.  So, we will steer the proton beam so it misses the beryllium target.  The protons will then strike a concrete barrier at the end of the decay tunnel.  Hence, neutrino production from decay-in-flight of the mesons will be minimized.  But, some theories predict that dark matter may be produced in the proton collisions.  We will try to detect the interaction of some of this dark matter in the detector.

Inside MiniBooNE Detector imageMiniBoone Neutrino Event image

Welcome to “The Fun is Real!” (Fun with Physics, that is)

Welcome to “The Fun Is Real“, a new blog that will explore wonders and mysteries of physics.  In particular, I am interested in the questions that are not yet understood.  These questions may be due to new experimental evidence that out-paces the theorists, like dark matter, dark energy, neutrino anomalies, etc.  Or it may be areas where the theory works, but we don’t have a conceptual understanding of how/why the universe does what it does.  One example of this is quantum physics and  quantum non-locality.

The Fun Is Real: wave-particle duality imageThe predictions of quantum mechanics have been confirmed, time and time again, by experimentalists, with greater precision than any other theory in the history of physics.  In the history of science, for that matter!  Additionally, the engineering breakthroughs that have created our information society, and the current trajectory of our technology, are dependent upon quantum mechanics.  Yet, we do not understand how the universe pulls off some of the tricks inherent in quantum physics.  We don’t understand why certain things are quantized.  And entangled particles seem to be able to affect each other over arbitrary distances, without regard to time.  I will expand more on these issues in future blogs.  I also invite your inputs and ideas on the discussions.

In addition to quantum non-locality, examples of other areas that you will see discussed here in the coming months include: (1) Given that a charged particle undergoing acceleration gives off electromagnetic radiation (i.e. emits photons), and a gravitational field is equivalent to acceleration, then why don’t charged particles emit photons simply due to being in a gravitational field? Or do they? (2) Would time exist if there were no matter? (3) Why does the universe insist upon the use of “imaginary”, or complex, numbers to communicate it’s behavior? (4) Where does inertia come from and why does gravitational mass appear to be the same as inertial mass?

I don’t accept anthropomorphic explanations.  That is, I don’t accept as adequate an argument that states “we would not be here if it were not so”.  That does not contribute to our understanding of the how/why of the universe.  I also don’t accept “the theory has to be that way to be consistent with the evidence”.  I want to understand.  I want to know why.  I want to know how.  I want to know how a particle can impact measurements done on it’s entangled partner, in apparent violation of locality and the speed of light; not just how to do the calculations.

This is a new website.  I am trying to make it interesting and accessible.  Let me know if you see problems or if you have ideas to make it better.  Remember, the physics may be theoretical, but “The Fun Is Real“.