Mad-Dog Everettianism: Quantum Mechanics at Its Most Minimal by Sean M. Carroll and Ashmeet Singh

Hi Sean and Ashmeet,

Thanks for this fascinating essay. I got a little lost in some of the details, but really enjoyed reading it nonetheless, and I love the ambition of deriving everything from such basic principles.

Quick question: what does the "mad dog" refer to??

Recently I've been interested in showing how objectivity -- a central part of classicality -- can emerge from a quantum substrate. A really nice paper showed that, whenever the system of interest is connected to a sufficiently large environment, objectivity emerges (i.e. different observers will agree on their measurements) even when no assumptions are placed on the Hilbert space or the Hamiltonian (https://arxiv.org/abs/1310.8640). I've been extending their results to infinite dimensions (paper in preparation!).

This is probably a naive thought, but I wonder if some of the other aspects you covered (space-time, gravity, etc) are also an inherent part of the mathematical structure of quantum mechanics, rather than being properties of the specific Hamiltonian or Hilbert space?

All the best,

Paul

Dear Sean Carroll

I read your critique on crackpot theorists. Cant say that endeared you to me, but I wont let that effect my judgment of the work you present now.

Just letting you know that I am making a start on reading of your essay, and hope that you might also take a glance over mine please? I look forward to the sharing of thoughtful opinion. Congratulations on your essay rating as it stands, and best of luck for the contest conclusion.

My essay is titled

"Darwinian Universal Fundamental Origin". It stands as a novel test for whether a natural organisational principle can serve a rationale, for emergence of complex systems of physics and cosmology. I will be interested to have my effort judged on both the basis of prospect and of novelty.

Thank you & kind regards

Steven Andresen

Respected Prof Sean Carroll

Dear Ashmeet Singh

You have very nicely interpreted that the "quantum mechanics" is one of the most fundamental things of the universe. ........ Many-Worlds interpretation, based on a vector in Hilbert space and a Hamiltonian vis a vis an algebra of preferred observables. You argue that even such an algebra is unnecessary, and even went for the most basic description of the world...... the spectrum of the Hamiltonian ..... wonderful logic sirs.... By the way...

Here in my essay energy to mass conversion is proposed................ yours is very nice essay best wishes .... I highly appreciate hope your essay and hope for reciprocity ....You may please spend some of the valuable time on Dynamic Universe Model also and give your some of the valuable & esteemed guidance

Some of the Main foundational points of Dynamic Universe Model :

-No Isotropy

-No Homogeneity

-No Space-time continuum

-Non-uniform density of matter, universe is lumpy

-No singularities

-No collisions between bodies

-No blackholes

-No warm holes

-No Bigbang

-No repulsion between distant Galaxies

-Non-empty Universe

-No imaginary or negative time axis

-No imaginary X, Y, Z axes

-No differential and Integral Equations mathematically

-No General Relativity and Model does not reduce to GR on any condition

-No Creation of matter like Bigbang or steady-state models

-No many mini Bigbangs

-No Missing Mass / Dark matter

-No Dark energy

-No Bigbang generated CMB detected

-No Multi-verses

Here:

-Accelerating Expanding universe with 33% Blue shifted Galaxies

-Newton's Gravitation law works everywhere in the same way

-All bodies dynamically moving

-All bodies move in dynamic Equilibrium

-Closed universe model no light or bodies will go away from universe

-Single Universe no baby universes

-Time is linear as observed on earth, moving forward only

-Independent x,y,z coordinate axes and Time axis no interdependencies between axes..

-UGF (Universal Gravitational Force) calculated on every point-mass

-Tensors (Linear) used for giving UNIQUE solutions for each time step

-Uses everyday physics as achievable by engineering

-21000 linear equations are used in an Excel sheet

-Computerized calculations uses 16 decimal digit accuracy

-Data mining and data warehousing techniques are used for data extraction from large amounts of data.

- Many predictions of Dynamic Universe Model came true....Have a look at

http://vaksdynamicuniversemodel.blogspot.in/p/blog-page_15.html

I request you to please have a look at my essay also, and give some of your esteemed criticism for your information........

Dynamic Universe Model says that the energy in the form of electromagnetic radiation passing grazingly near any gravitating mass changes its in frequency and finally will convert into neutrinos (mass). We all know that there is no experiment or quest in this direction. Energy conversion happens from mass to energy with the famous E=mC2, the other side of this conversion was not thought off. This is a new fundamental prediction by Dynamic Universe Model, a foundational quest in the area of Astrophysics and Cosmology.

In accordance with Dynamic Universe Model frequency shift happens on both the sides of spectrum when any electromagnetic radiation passes grazingly near gravitating mass. With this new verification, we will open a new frontier that will unlock a way for formation of the basis for continual Nucleosynthesis (continuous formation of elements) in our Universe. Amount of frequency shift will depend on relative velocity difference. All the papers of author can be downloaded from "http://vaksdynamicuniversemodel.blogspot.in/ "

I request you to please post your reply in my essay also, so that I can get an intimation that you replied

Best

=snp

Dear Sean and Asmheet,

you gave a nice intuition on your research program. In fact given a wave function of the universe and a Hamiltonian governing the evolution, one should in principle be able to derive our observable universe. Of course the reverse engineering from our observable universe to the universal wave function is much more difficult.

My approach to the quantum measurement problem is similar to Everett's relative state formulation of quantum mechanics, but with no branching and no external decoherence.

As in your essay a quantum measurement is described as consisting of 3 systems: the quantum system Hq, the apparatus Ha and the environment (or the rest of the universe) He. The time evolution is given such, that all the 3 systems can get entangled. However contrary to the decoherence program I assume, that the environment must be in a very special symmetric state, such that the environment does not get entangled with the Hq and Ha subsystem. Such states of the environment exists. The evolution on the subsystem can be described by a unitary evolution. This is a condition that the properties of Hq can be measured or defined. The (from within the system) unobservable absolute quantities can be averaged out, which reduces the density matrix of the subsystem. This reduction is objective and immune against Wigner's friend type objections because if Wigner (the environment) would like to observe the system it must get entangled with the subsystem. But then the conditions of a successful measurement would be broken.

I would love, if you find the time to comment on my essay The quantum sheep - In defence of a positivist view on physics.

Best regards

Luca

Sean, Asmheet,

I think that's the best description of Many Worlds I've read. Very interesting, well written and explained.

However. I do derive a finding in my essay which suggests that either you may "..have just gone mad.", or more likely that NO 'interpretation' beyond classical mechanics may be needed!! (I was conservative with the exclamation marks). Which is exactly as John Bell believed and stated.

Few are qualified to analyse the sequence of ontological mechanisms reproducing QM's predictions, I hope you are; I've just written a short outline on John Klauders string which will assist.

Declan Traill's short essay confirms the matching code gives the CHSH >2 Cos^2 plots as well as the steering >1 closing the detector loophole. My top scored 2015 'red/green sock trick' essay started the construction (as a test of a rational SR solution). Shockingly if correct there is no 'non-locality' and QM and SR unify!

I look forward to questions.

Well done for your excellent essay anyway.

Peter Jackson

Hi Sean and Ashmeet:

Enjoyed your well-written and enlightening essay, especially the discussion regarding the fundamental ontology of QM.

It is intriguing that while quantum theory describes the evolution of a state vector in a complex Hilbert space, I present a simple relativity based model that describes the universal physical reality as a set of relativistic mass/energy/space/time states in various frames of observer references with varying velocity V. Using this model, we can bridge the gap between quantum and relativistic ontology without the need of uncertainty and statistical nature of quantum mechanics. My model shows that the fundamental reality is relativistic and not quantum. Heisenberg's uncertainty is shown to be an artifact of the measurement error caused by measuring a dominantly relativistic (commonly labelled as quantum, V close to C) phenomenon with dilated space-time in a classical fixed space-time.

In my paper- "What is Fundamental - Is C the Speed of Light", I propose the missing physics of spontaneous mass-energy conversion (as observed in wave-particle behavior) that bridges QM and relativity while resolving the paradox of the missing dark energy that is revealed as the relativistic kinetic energy and the model derives a physics based mathematical equation (no more a fudge constant) for the Cosmological Constant . It also resolves the paradox of the collapse of the wave function that is explained via transition to the classical space-time from the fully dilated space-time when a measurement is made, the black hole singularity of GR eliminated via mass dilation at small R, and solution is obtained to other current inconsistencies as well as weirdness (QM) of mainstream theories as described in my book.

I would greatly appreciate your time and feedback on my paper?

Thanking you in advance,

Best Regards

Avtar Singh

Such a great place where you play stickman games free online games completely free of cost.

Dear Sean

If you are looking for another essay to read and rate in the final days of the contest, will you consider mine please? I read all essays from those who comment on my page, and if I cant rate an essay highly, then I don't rate them at all. Infact I haven't issued a rating lower that ten. So you have nothing to lose by having me read your essay, and everything to gain.

Beyond my essay's introduction, I place a microscope on the subjects of universal complexity and natural forces. I do so within context that clock operation is driven by Quantum Mechanical forces (atomic and photonic), while clocks also serve measure of General Relativity's effects (spacetime, time dilation). In this respect clocks can be said to possess a split personality, giving them the distinction that they are simultaneously a study in QM, while GR is a study of clocks. The situation stands whereby we have two fundamental theories of the world, but just one world. And we have a singular device which serves study of both those fundamental theories. Two fundamental theories, but one device? Please join me and my essay in questioning this circumstance?

My essay goes on to identify natural forces in their universal roles, how they motivate the building of and maintaining complex universal structures and processes. When we look at how star fusion processes sit within a "narrow range of sensitivity" that stars are neither led to explode nor collapse under gravity. We think how lucky we are that the universe is just so. We can also count our lucky stars that the fusion process that marks the birth of a star, also leads to an eruption of photons from its surface. And again, how lucky we are! for if they didn't then gas accumulation wouldn't be halted and the star would again be led to collapse.

Could a natural organisation principle have been responsible for fine tuning universal systems? Faced with how lucky we appear to have been, shouldn't we consider this possibility?

For our luck surely didnt run out there, for these photons stream down on earth, liquifying oceans which drive geochemical processes that we "life" are reliant upon. The Earth is made up of elements that possess the chemical potentials that life is entirely dependent upon. Those chemical potentials are not expressed in the absence of water solvency. So again, how amazingly fortunate we are that these chemical potentials exist in the first instance, and additionally within an environment of abundant water solvency such as Earth, able to express these potentials.

My essay is attempt of something audacious. It questions the fundamental nature of the interaction between space and matter Guv = Tuv, and hypothesizes the equality between space curvature and atomic forces is due to common process. Space gives up a potential in exchange for atomic forces in a conversion process, which drives atomic activity. And furthermore, that Baryons only exist because this energy potential of space exists and is available for exploitation. Baryon characteristics and behaviours, complexity of structure and process might then be explained in terms of being evolved and optimised for this purpose and existence. Removing need for so many layers of extraordinary luck to eventuate our own existence. It attempts an interpretation of the above mentioned stellar processes within these terms, but also extends much further. It shines a light on molecular structure that binds matter together, as potentially being an evolved agency that enhances rigidity and therefor persistence of universal system. We then turn a questioning mind towards Earths unlikely geochemical processes, (for which we living things owe so much) and look at its central theme and propensity for molecular rock forming processes. The existence of chemical potentials and their diverse range of molecular bond formation activities? The abundance of water solvent on Earth, for which many geochemical rock forming processes could not be expressed without? The question of a watery Earth? is then implicated as being part of an evolved system that arose for purpose and reason, alongside the same reason and purpose that molecular bonds and chemistry processes arose.

By identifying atomic forces as having their origin in space, we have identified how they perpetually act, and deliver work products. Forces drive clocks and clock activity is shown by GR to dilate. My essay details the principle of force dilation and applies it to a universal mystery. My essay raises the possibility, that nature in possession of a natural energy potential, will spontaneously generate a circumstance of Darwinian emergence. It did so on Earth, and perhaps it did so within a wider scope. We learnt how biology generates intricate structure and complexity, and now we learn how it might explain for intricate structure and complexity within universal physical systems.

To steal a phrase from my essay "A world product of evolved optimization".

Best of luck for the conclusion of the contest

Kind regards

Steven Andresen

Darwinian Universal Fundamental Origin

Dean Sean and Singh,

This was very impressive. This program seems to me very difficult, but you made it look very natural and the advances are impressive. I don't believe in MWI, but I am sure that in a parallel world you convinced me :)) (just kidding!)

There's something that bothers me for some time. You said that the Hilbert space of a compact region of space is finite-dimensional. This is something I hear, also in relation to black hole entropy, but can it work without imposing some additional constraints, like the wavefunctions having the support either included in the region or completely outside? And I think this condition is not justified, because: (1) the electron in an atom is spread in the entire space, (2) a wavefunction which is confined to a compact region immediately after spreads everywhere, (3) the Feynman diagrams include unlimited number of particles, so the Fock space on that region has to include the subspaces of any dimension. Consequently, it seems to me that the wavefunctions of the particles inside the region should have tails outside and vice-versa, resulting in an infinite-dimensional Hilbert space. The collapse into a black hole doesn't happen in this case because most particles are outside. If we impose the condition which leads to finite dimensional Hilbert space, I expect indeed that this will impose a cut-off on the Feynman graphs, but what justifies such a condition? On the other hand I agree that atoms can be located in regions of space, so maybe there is a weaker conditions and the tails are allowed to be outside, but in this case what makes the Hilbert space finite-dimensional?

Thank you in advance for any clarification of the above.

I was very skeptical few years ago that one can get a universe like the one we observe just out of psi, H, and the Hilbert space, mainly because the unitary symmetry seemed to me to remove any difference between the positions and other observables. I realized that the interaction Hamiltonian has to be local, and that by finding the symmetries of the Hamiltonian and psi we can recover spacetime, elementary particles, and all that. I am still suspicious about the classical level, it seems to me that it requires to find new laws which impose constraints on the wavefunction or interactions which remove the Schrödinger cats. The alternative is to prove that decoherence solves it, which is another ambitious program (which I see as a subprogram of MWI and other interpretations like Bohm's as well). To me a solution of the measurement problem and the emergence of classicality via decoherence seems sometimes trivial, sometimes impossible, so maybe the truth is in between.

There's something I saw in your essay which made me think that you may enjoy, at leisure time, this sci-fi short story called Quantum God (spoiler: is not religious :)) )

Congratulations and thanks again for this excellent essay!

Best wishes,

Cristi Stoica, Indra's net

Everett's work was debunked many time ago, both in physical and mathematical grounds. Alternative attempts presented in the last 50 years by Graham, DeWitt, Geroch, Deuthch,... have been debunked as well.

Not only Many-Worlds isn't a valid interpretation of QM, but its proponents disagree. E.g. Deuth's Many-Worlds is not Everett's Many-Worlds. Next link contains rebuttal of early Everett ideas

http://www.mat.univie.ac.at/~neum/physfaq/topics/manyworlds

"Quantum theory describes the evolution of a state vector in a complex Hilbert space, but we populate our theories with ideas like "spacetime", "particles," and "fields"." That is a very narrow conception of quantum theory because, for instance, the quantum state of an unstable system isn't given by any state vector in a Hilbert space. We populate our theories with concepts as particles because they are the basic building blocks of Nature.

Equation (1) is an approximation. It doesn't apply to system in mixed states, neither to irreversible phenomena. The notation used is also inadequate. If the state vector is only a function of time, then a partial derivative makes little sense; a total derivative would be used.

"The lesson we draw from this is that Nature at its most fundamental is simply described by a vector in Hilbert space". As mentioned above, this isn't true. What is more, even for those systems adequately described by ordinary state vector theory, it is possible to find alternative formulations without Hilbert spaces or vectors. A well-known example is the Wigner-Moyal formulation of quantum mechanics. Hilbert space and state vectors are replaced by non-commutative phase space and Wigner function W(p,q). One evident advantage of the Wigner-Moyal formulation is that is also works for quantum systems for which the Hilbert formulation doesn't work.

"Classical concepts must emerge from this structure in an appropriate limit". It has been rigorously demonstrated that classical systems aren't contained in a Hilbert space structure. And that is the reason why many physicists and mathematicians are working in extensions of quantum theory. The old theory is being extended at two levels: generalized spaces beyond Hilbert space, and nonlinear extensions of Schrödinger equation.

Eq (3) is only valid for quantum systems with discrete spectrum. The complete spectral decomposition of the Hamiltonian operator is given in the attachment.

"One might ask why, if the fundamental theory of everything is fixed by the spectrum of some Hamiltonian, we don't simply imagine writing the state of the universe in the energy eigenbasis, where its evolution is trivial?" Because we know a spectral decomposition of the Hamiltonian doesn't fix "everything".

"Consider the classical theory of N particles moving under the influence of some multi-particle potential in 3 dimensions of space. The corresponding phase space is 6N-dimensional, and we could simply think of the theory as that of one point moving in a 6N-dimensional structure. But by thinking of it as N particles moving in a 3-dimensional space of allowed particle positions, we gain enormous intuition; for example, it could become clear that particles in uence each other when they are nearby in space, which in turn suggests a natural way to coarse-grain the theory". This class of reasoning is what confused Boltzmann and a several generations of physicists. The classical state is given by a point in the 6N phase-space. A model of N particles moving in a 3-dimensional space (really 6-dimensional) fails to consider subtle elements of the full dynamics, such as the existence of long-range correlations. Coarse graining the the theory over distances larger than the range of the interactions will erase the correlations that are needed to drive systems to stable equilibrium.

Similar remarks about (8) and (9).

"This procedure is crucial to the Everettian program, where the interaction of systems with their environment leads to decoherence and branching of the wave function [...] The Born Rule for probabilities, p(i) = |Psi_i@|2, isn't assumed as part of the theory; it can be derived using techniques such as decision theory [12] or self-locating uncertainty [13]". The Born rule isn't compatible with the kind of unitary evolution this Essay is assuming. So it cannot be derived. At best, the rule can be introduced ad hoc as an additional postulate, but then we have the same dual-evolution inconsistency than in the traditional Copenhagen treatment.

"The former condition is ultimately cosmological -- the universe started in a low-entropy state, which we won't discuss here". But equation (1) conserves entropy, and cannot describe evolution to current state.

"The essential observation is that, if quantum behavior is distinguished from classical behavior by the presence of entanglement, classical behavior may be said to arise when entanglement is relatively unimportant". Another old argument has been refuted again and again in the literature. Eliminating the entanglement simply provides a mixture with only diagonal elements in the density matrix, but this is not the classical state; reason why the founding fathers of QM introduced an additional postulate to complement the postulate about Schrödinger evolutions.

Next section is based in many assumptions and unproven statements, some of them explicitly assumed "although it's unclear how to achieve this at this time".

WdW equation is incorrect. In fact one of his authors even renounced to it considering it "a very bad equation". Further attempts to extract a valid concept of time from it are condemned to failure. The problem is not the "clock ambiguity", the real problem is that time is an evolution parameter, not an observable one can get from a spectrum.