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We consider the entanglement marginal problem, which consists of deciding whether a number of reduced density matrices are compatible with an overall separable quantum state. To tackle this problem, we propose hierarchies of semidefinite…

Quantum Physics · Physics 2021-11-30 Miguel Navascues , Flavio Baccari , Antonio Acin

The aim of this paper is to find the exact solutions of the Schrodinger equation. As is known, the Schrodinger equation can be reduced to the continuum equation. In this paper, using the non-linear Legendre transform the equation of…

Quantum Physics · Physics 2018-10-17 E. E. Perepelkin , B. I. Sadovnikov , N. G. Inozemtseva , A. A. Tarelkin

Boundary value problems for the nonlinear Schrodinger equation on the half line in laboratory coordinates are considered. A class of boundary conditions that lead to linearizable problems is identified by introducing appropriate extensions…

Exactly Solvable and Integrable Systems · Physics 2018-11-21 Katelyn Plaisier Leisman , Gino Biondini , Gregor Kovacic

Significant advances in the development of computing devices based on quantum effects and the demonstration of their use to solve various problems have rekindled interest in the nature of the "quantum computational advantage." Although…

Quantum Physics · Physics 2024-11-01 Aleksey K. Fedorov , Evgeniy O. Kiktenko , Nikolay N. Kolachevsky

We introduce the concept of a "classical observable" as an operator with vanishingly small quantum fluctuations on a set of density matrices. It is shown how to construct them for a time evolved pure state. The study of classical…

Quantum Physics · Physics 2014-04-29 Michiel Wouters

The time-dependent Schrodinger equation is solved for two model problems for a non-Hermitian quantum system.A simple matrix model system is used to examine two critical problems for these systems: complex and non-observable energies and…

Quantum Physics · Physics 2024-12-11 Brian L Burrows

Quantum simulation is known to be capable of simulating certain dynamical systems in continuous time -- Schrodinger's equations being the most direct and well-known -- more efficiently than classical simulation. Any linear dynamical system…

Quantum Physics · Physics 2025-04-22 Shi Jin , Nana Liu

Schroedinger's famous thought experiment involves a (macroscopic) cat whose quantum state becomes entangled with that of a (microscopic) decaying nucleus. The creation of such micro-macro entanglement is currently being pursued in several…

Quantum Physics · Physics 2015-06-12 A. I. Lvovsky , R. Ghobadi , A. Chandra , A. S. Prasad , C. Simon

We present a panoramic view on various attempts to "solve" the problems of quantum measurement and macro-objectivation, i.e. of the transition from a probabilistic quantum mechanic microscopic world to a deterministic classical macroscopic…

Quantum Physics · Physics 2010-05-05 M. Genovese

An introduction to some basic ideas of the author's "quantum cybernetics" is given, which depicts waves and "particles" as mutually dependent system components, thus defining "organizationally closed systems" characterized by a fundamental…

Quantum Physics · Physics 2007-05-23 Gerhard Groessing

Schr\"odinger equation with given, {\it a priori} known current is formulated. A non-zero current density is maintained in the quantum system via a subsidiary condition imposed by vector, local Lagrange multiplier. Constrained minimization…

Condensed Matter · Physics 2009-11-07 D. S. Kosov

Hallmarks of quantum mechanics include superposition and entanglement. In the context of large complex systems, these features should lead to situations like Schrodinger's cat, which exists in a superposition of alive and dead states…

Determining the initial state of the universe is a challenging problem in quantum cosmology and we argue that the issue is intractable if the basic postulates of quantum mechanics are not modified in a nontrivial way. Namely a "standard"…

General Relativity and Quantum Cosmology · Physics 2019-10-09 Ali Kaya

We shed new light on entanglement measures in multipartite quantum systems by taking a computational-complexity approach toward quantifying quantum entanglement with two familiar notions--approximability and distinguishability. Built upon…

Quantum Physics · Physics 2007-05-23 Tomoyuki Yamakami

The time-dependent quantum system of two laser-driven electrons in a harmonic oscillator potential is analysed, taking into account the repulsive Coulomb interaction between both particles. The Schrodinger equation of the two-particle…

Quantum Physics · Physics 2009-11-07 Uwe Schwengelbeck

The problem of interpreting quantum theory on a large (e.g. cosmological) scale has been commonly conceived as a search for objective reality in a framework that is fundamentally probabilistic. The Everett programme attempts to evade the…

High Energy Physics - Theory · Physics 2009-11-10 Brandon Carter

A nonperturbative procedure of solving the time-dependent Schr\"odinger equation, called the multi-projection approach or phase dynamics of quantum mechanics, is derived and illustrated. In addition to introducing a method with that…

Quantum Physics · Physics 2007-05-23 C. Y. Chen

An exactly solvable position-dependent mass Schr\"odinger equation in two dimensions, depicting a particle moving in a semi-infinite layer, is re-examined in the light of recent theories describing superintegrable two-dimensional systems…

Mathematical Physics · Physics 2008-04-24 Christiane Quesne

Quantum theory is applicable, in principle, to both the microscopic and macroscopic realms. It is therefore worthwhile to investigate whether it is possible to evolve a quantum-compatible view of the properties and states of macroscopic…

Quantum Physics · Physics 2007-08-14 Ravi Gomatam

In this paper we derive the Schroedinger equation by assuming it describes the time evolution of a deterministic and reversible process that leaves at each moment in time a different observable well defined; that is, it allows an accurate…

Quantum Physics · Physics 2008-09-08 Gabriele Carcassi