English
Related papers

Related papers: No Time Asymmetry from Quantum Mechanics

200 papers

When excited states decay the time evolution operator $U(t)=e^{-iHt}$ does not obey $U^{\dagger}(t)U(t)=I$. Nonetheless, probability conservation is not lost if one includes both excitation and decay, though it takes a different form.…

Quantum Physics · Physics 2025-05-14 Philip D. Mannheim

In recent years, the breakdown of spacetime symmetries has been identified as a promising research field in the context of Planck-scale phenomenology. For example, various theoretical approaches to the quantum-gravity problem are known to…

High Energy Physics - Phenomenology · Physics 2009-10-08 Ralf Lehnert

We examine consequences of the density matrix approach to quantum theory in the context of a model spacetime containing closed timelike curves and find that in general, an initially pure state will evolve in a nonlinear way to a mixed…

General Relativity and Quantum Cosmology · Physics 2009-10-22 M. J. Cassidy

Non-commutative spacetime and quantum groups have been argued to capture non-classical features of spacetime and its symmetries in the low-energy limit of quantum gravity. In this letter, we show that employing the $SU_q(2)$ quantum group…

Quantum Physics · Physics 2026-05-29 Vittorio D'Esposito , Giuseppe Fabiano , Domenico Frattulillo

While fundamental physically realistic Hamiltonians should be invariant under time reversal, time asymmetric Hamiltonians can occur as mathematical possibilities or effective Hamiltonians. Here, we study conditions under which…

Quantum Physics · Physics 2019-08-01 Julian Schmidt , Roderich Tumulka

Longstanding anomalies in the Cosmic Microwave Background (CMB), including the low quadrupole moment and hemispherical power asymmetry, have recently been linked to an underlying parity asymmetry. We show here how this parity asymmetry…

General Physics · Physics 2025-07-08 Enrique Gaztañaga , K. Sravan Kumar

The predictions of the Bohmian and the decoherent (or consistent) histories formulations of the quantum mechanics of a closed system are compared for histories -- sequences of alternatives at a series of times. For certain kinds of…

Quantum Physics · Physics 2009-11-07 James B. Hartle

We show that a quantum system possessing an exact antilinear symmetry, in particular PT-symmetry, is equivalent to a quantum system having a Hermitian Hamiltonian. We construct the unitary operator relating an arbitrary non-Hermitian…

Quantum Physics · Physics 2008-11-26 Ali Mostafazadeh

Within the decoherent histories formulation of quantum mechanics, we consider arbitrarily long histories constructed from a fixed projective partition of a finite-dimensional Hilbert space. We review some of the decoherence properties of…

Quantum Physics · Physics 2009-11-10 Artur Scherer , Andrei N. Soklakov

On the basis of a 5-dimensional form of space-time transformations non-relativistic quantum mechanics is reformulated in a manifestly covariant manner. The resulting covariance resembles that of the conventional relativistic quantum…

Quantum Physics · Physics 2007-05-23 Minoru Omote , Susumu Kamefuchi

Einstein-Podolsky-Rosen's paper in 1935 is discussed in parallel with an EPR experiment on $K^0\bar{K}^0$ system in 1998, yielding a strong hint of distinction in both wave-function and operators between particle and antiparticle at the…

General Physics · Physics 2012-07-24 Guang-jiong Ni , Suqing Chen , Jianjun Xu

Close to the Planck energy scale, the quantum nature of space-time reveals itself and all forces, including gravity, should be unified so that all interactions correspond to just one underlying symmetry. In the absence of a full quantum…

High Energy Physics - Theory · Physics 2015-03-17 Mairi Sakellariadou

The rules of quantum mechanics require a time coordinate for their formulation. However, a notion of time is in general possible only when a classical spacetime geometry exists. Such a geometry is itself produced by classical matter…

Quantum Physics · Physics 2007-05-23 T. P. Singh

The quantum mechanical transition probability is symmetric. A probabilistically motivated and more general quantum logical definition of the transition probability was introduced in two preceding papers without postulating its symmetry, but…

Quantum Physics · Physics 2023-12-20 Gerd Niestegge

We pursue the view that quantum theory may be an emergent structure related to large space-time scales. In particular, we consider classical Hamiltonian systems in which the intrinsic proper time evolution parameter is related through a…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Hans-Thomas Elze

We reconsider the Decoherent Histories approach to Quantum Mechanics and we analyze some problems related to its interpretation which, according to us, have not been adequately clarified by its proponents. We put forward some assumptions…

Quantum Physics · Physics 2007-05-23 Angelo Bassi , GianCarlo Ghirardi

I will provide a pedagogical introduction to non-Hermitian quantum systems that are PT-symmetric, that is they are left invariant under a simultaneous parity transformation (P) and time-reversal (T). I will explain how generalised versions…

Quantum Physics · Physics 2023-02-27 Andreas Fring

We propose construction of a unique and definite metric ($\eta_+$), time-reversal operator (T) and an inner product such that the pseudo-Hermitian matrix Hamiltonians are C, PT, and CPT invariant and PT(CPT)-norm is indefinite (definite).…

Quantum Physics · Physics 2009-11-10 Zafar Ahmed

Parks introduced a formulation of time dependent weak values in 2008, which is the formalism we use in this paper. In this paper we extend notions from time dependent weak values to show that Hamiltonians associated with weak value…

Quantum Physics · Physics 2021-11-22 A. D. Parks , J. E. Gray , G. K Josemans

We present a relativistic quantum mechanics of a point mass with absolute thermodynamic time and temperature, combined to a single complex parameter of evolution. In this theory, the geometric time is introduced as one of space-time…

High Energy Physics - Theory · Physics 2007-05-23 Vadim V. Asadov , Oleg V. Kechkin