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arXiv:1710.08419

Quantum Mechanics from Ergodic Average of Microstates

Marco Matone

Published Oct 23, 2017• 0 citations
arXivHTMLPDF

Abstract

We formulate quantum mechanics as an effective theory of an underlying structure characterized by microstates $|{\mathcal M}^j(t)\rangle$, each one defined by the quantum state $|Ψ(t)\rangle$ and a complete set of commutative observables $O^j$. At any time $t$, $|{\mathcal M}^j(t)\rangle$ corresponds to a state $|O^j_k\rangle$, for some $k$ depending on $t$, and jumps after time intervals whose duration, of the order of the Compton time $τ$, is proportional to the probability $|\langle O_k^j|Ψ(t)\rangle|^2$. This reproduces the Born rule and mimics the wave-particle duality. The theory is based on a partition of time whose flow is characterized by quantum probabilities. Ergodicity arises at ordinary quantum scales with the expectation values corresponding to time averaging over a period $τ$. The measurement of $O^j$ provides a new partition of time and the outcome is the state $|O_k^j\rangle$ to which $|{\mathcal M}^j(t)\rangle$ corresponds at that time. The formulation, that shares some features with the path integral, can be tested by experiments involving time intervals of order $τ$.

DOI
10.48550/arxiv.1710.08419

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The Born rule may be stated mathematically as the rule that probabilities in quantum theory are expectation values of a complete orthogonal set of projection operators. This rule works for single laboratory settings in which the observer can distinguish all the different possible outcomes corresponding to the projection operators. However, theories of inflation suggest that the universe may be so large that any laboratory, no matter how precisely it is defined by its internal state, may exist in a large number of very distantly separated copies throughout the vast universe. In this case, no observer within the universe can distinguish all possible outcomes for all copies of the laboratory. Then normalized probabilities for the local outcomes that can be locally distinguished cannot be given by the expectation values of any projection operators. Thus the Born rule fails and must be replaced by another rule for observational probabilities in cosmology. The freedom of what this new rule is to be is the measure problem in cosmology. A particular volume-averaged form is proposed.
This paper addresses the foundational question deferred by Paper VII: why does the multiplicity Omega of U-field microstates combine as the squared modulus of a complex amplitude? We argue that if the coarse-grained U-field microstate sum admits a path-integral representation over field configurations with phase weights exp(iS/hbar_eff), then a Complex Multiplicity Amplitude Z(Y) is associated with each outcome Y. Via a Constraint Surface Geometry argument, we show that the effective multiplicity must take the form Omega(Y) = |Z(Y)|^n by phase invariance and multiplicativity, and the empirically observed bilinear interference structure selects n=2, yielding Omega(Y) = |Z(Y)|^2. The Born rule P proportional to |psi|^2 then follows from the multiplicity principle P proportional to Omega together with the identification psi proportional to Z. Interference arises from linear addition of complex amplitudes before squaring; classical probability addition is recovered via decoherence. The outcome-selection rule (the Probabilistic Bias Functional B) is grounded in the ergodic/mixing dynamics of the Tier-1 lattice, conditional on mixing within the accessible phase-space sector. The construction of the path-integral measure from U-field microstate counting remains an open problem. This is the eighth paper in the 18-paper USSFT technical series; for the U-field Lagrangian foundations see Papers I-VI, for the quantum mechanics operator formalism see Paper VII (DOI: 10.5281/zenodo.19675374), and for spin structure and Bell correlations see Paper IX.
The study of quantum statistical mechanics begins with a review of the basic principles of quantum mechanics. Schrödinger’s equation is introduced and Eigenstates (or stationary states) are defined. Model probability for quantum statistics is assumed to have a uniform distribution in phases. Wave functions for many-body systems are defined. The density matrix is introduced. The Planck entropy and the microcanonical ensemble are defined. The differences between classical and quantum statistical mechanics are all based on the differing concepts of a microscopic ‘state’. While the classical microscopic state (specified by a point in phase space) determines the exact position and momentum of every particle, the quantum mechanical state determines neither; quantum states can only provide probability distributions for observable quantities.
A type of mechanics will be presented that possesses some distinctive properties. On the one hand, its physical description & rules of operation are readily comprehensible & intuitively clear. On the other, it fully satisfies all observable predictions of non-relativistic quantum mechanics. Within it, particles exist at points in space, follow continuous, piecewise differentiable paths, and their linear momentum is equal to their mass times their velocity along their path. Yet the probabilities for position and momentum, conditioned on the state of the particle's environment, follow the rules of quantum theory. Indeed, all observable consequences of quantum theory are satisfied; particles can be entangled, have intrinsic spin, this spin is not local to the particle, particle identity can effect probabilities, and so forth. All the rules of quantum mechanics are obeyed, and all arise in a straightforward fashion. After this is established, connections will be drawn out between this type of mechanics and other types of quantum worlds; those that obey Bohmian mechanics, stochastic mechanics, the many worlds interpretation, and physical collapse. In the final section, a relativistic version of the mechanics will be presented.