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Related papers: Energy Non-Conservation in Quantum Mechanics

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We construct a measure in the hamiltonian function level sets that is invariant under the hamiltonian flow for short times and flow preserving for arbitrarily long times. This allows a probabilistic approach to the study of hamiltonian…

Mathematical Physics · Physics 2026-04-29 Luis A. Cedeño-Pérez , Alexis E. López-Velázquez

A collapse-free version of quantum theory is examined to systematically study the role of the projection postulate. This foil theory assumes "passive" measurements that do not update quantum states although measurement outcomes still occur…

Quantum Physics · Physics 2025-08-27 Vincenzo Fiorentino , Stefan Weigert

We show that due to entanglement, quantum fluctuations may differ significantly from statistical fluctuations. We calculate quantum fluctuations of the particle number and of the energy in a sub-volume of a system of bosons in a pure state,…

High Energy Physics - Theory · Physics 2008-11-26 Ram Brustein , Amos Yarom

Concise, accurate descriptions of physical systems through their conserved quantities abound in the natural sciences. In data science, however, current research often focuses on regression problems, without routinely incorporating…

Computational Physics · Physics 2020-02-05 Tom Bertalan , Felix Dietrich , Igor Mezić , Ioannis G. Kevrekidis

The problem of sampling outputs of quantum circuits has been proposed as a candidate for demonstrating a quantum computational advantage (sometimes referred to as quantum "supremacy"). In this work, we investigate whether quantum advantage…

Quantum Physics · Physics 2021-06-09 Leonardo Novo , Juani Bermejo-Vega , Raúl García-Patrón

This recreational paper investigates what happens if we change quantum mechanics in several ways. The main results are as follows. First, if we replace the 2-norm by some other p-norm, then there are no nontrivial norm-preserving linear…

Quantum Physics · Physics 2007-05-23 Scott Aaronson

Examination of the Einstein energy-momentum relationship suggests that simple unbound forms of matter exist in a four-dimensional Euclidean space. Position, momentum, velocity, and other vector quantities can be expressed as Euclidean…

Quantum Physics · Physics 2007-05-23 Paul J. Freitas

Waves are propagating disturbances that redistribute energy across space. Previous studies have shown that for waves propagating through an inhomogeneously moving mean flow, the conserved quantity is wave action rather than wave energy,…

Fluid Dynamics · Physics 2025-04-29 Zhaohua Wu , Jie Sun , Zhe-Min Tan , Ming Cai , Yongyun Hu , Norden E. Huang

It has recently been shown that small quantum subsystems generically equilibrate, in the sense that they spend most of the time close to a fixed equilibrium state. This relies on just two assumptions: that the state is spread over many…

Quantum Physics · Physics 2015-05-30 Anthony J. Short , Terence C. Farrelly

In this article, we address the problem of how temperature of a quantum system is observed. By proposing a thought experiment, we argue that temperature must be conceived as an operator and its measurement must necessarily accompany a…

Quantum Physics · Physics 2018-07-19 Sushrut Ghonge , Dervis Can Vural

A number of issues related to measurement show that self-consistency is lacking in quantum mechanics as this theory has been generally understood. Each issue is presented as a point in this paper. Each point can be resolved by incorporating…

General Physics · Physics 2007-05-23 D. M. Snyder

We propose a new quantum computational way of obtaining a ground-state energy and expectation values of observables of interacting Hamiltonians. It is based on the combination of the adiabatic quantum evolution to project a ground state of…

Quantum Physics · Physics 2009-10-31 Sangchul Oh

The perturbative approach was adopted to develop a temperature-dependent version of non-relativistic quantum mechanics in the limit of low-enough temperatures. A generalized, self-consistent Hamiltonian was therefore constructed for an…

Quantum Physics · Physics 2021-03-08 Ashkan Shekaari , Mahmoud Jafari

In the context of the measurement problem, we propose to model the interaction between a quantum particle and an "apparatus" through a non-Hermitian Hamiltonian term. We simulate the time evolution of a normalized quantum state split into…

Quantum Physics · Physics 2024-04-26 Jorge Martinez Romeral , Luis E. F. Foa Torres , Stephan Roche

A heat engine undergoes a cyclic operation while in equilibrium with the net result of conversion of heat into work. Quantum effects such as superposition of states can improve an engine's efficiency by breaking detailed balance, but this…

Quantum Physics · Physics 2013-03-07 Sahand Hormoz

The current revolution in quantum technologies relies on the ability to isolate, coherently control, and measure the state of quantum systems. The act of measurement in quantum mechanics, however, is naturally invasive as the measurement…

Suppose a quantum system starts to evolve under a Hamiltonian from some initial state. When for the first time, will an observable attain a preassigned value? To answer this question, one method often adopted is to make instantaneous…

Quantum Physics · Physics 2016-06-01 Shrabanti Dhar , Subinay Dasgupta

In an expanding universe the vacuum energy density \rho_{\Lambda} is expected to be a dynamical quantity. In quantum field theory in curved space-time \rho_{\Lambda} should exhibit a slow evolution, determined by the expansion rate of the…

High Energy Physics - Phenomenology · Physics 2015-06-04 Harald Fritzsch , Joan Sola

In quantum mechanics, measurements cause wavefunction collapse that yields precise outcomes, for non-commuting observables such as position and momentum Heisenberg's uncertainty principle limits the intrinsic precision of a state. Although…

We review the physical phenomena that arise when quantum mechanical energy levels are modulated in time. The dynamics resulting from changes in the transition frequency is a problem studied since the early days of quantum mechanics. It has…

Quantum Physics · Physics 2017-04-07 M. P. Silveri , J. A. Tuorila , E. V. Thuneberg , G. S. Paraoanu