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The electron density $n(\rb,t)$, which is the central tool of time-dependent density functional theory, is presently considered to be derivable from a one-body time-dependent potential $V(\rb,t)$, via one-electron wave functions satisfying…

Quantum Physics · Physics 2009-04-28 Thomas A. Niehaus , Norman H. March

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

The coupling between internal degrees of freedom of quantum systems and their overall motion in an external gravitational field plays a central role in multiple extensions of Einstein's equivalence principle to quantum physics. While…

General Relativity and Quantum Cosmology · Physics 2026-03-04 Thomas B. Mieling

We shall show that the abstract and formal rules which govern the quantum kinematic and dynamics can be derived from a law of change of the information content or the degree of uncertainty that the system has a certain configuration in a…

Quantum Physics · Physics 2014-04-07 Agung Budiyono

We consider the loop quantization of Maxwell theory. A quantization of this type leads to a quantum theory in which the fundamental excitations are loop-like rather than particle-like. Each such loop plays the role of a quantized Faraday's…

High Energy Physics - Theory · Physics 2009-10-30 Alejandro Corichi , Kirill Krasnov

Quantum mechanics with a generalized uncertainty principle arises through a representation of the commutator $[\hat{x}, \hat{p}] = i f(\hat{p})$. We apply this deformed quantization to free scalar field theory for $f_\pm =1\pm \beta p^2$.…

High Energy Physics - Theory · Physics 2013-02-28 Viqar Husain , Dawood Kothawala , Sanjeev S. Seahra

We derive a generalized quantum Langevin equation and its fluctuation-dissipation relation describing the quantum dynamics of a tagged particle interacting with a medium (environment), where both the particle and the environment are driven…

Quantum Physics · Physics 2025-07-11 Daniele Gamba , Bingyu Cui , Alessio Zaccone

Variational quantum algorithms that are used for quantum machine learning rely on the ability to automatically differentiate parametrized quantum circuits with respect to underlying parameters. Here, we propose the rules for differentiating…

Quantum Physics · Physics 2021-11-16 Oleksandr Kyriienko , Vincent E. Elfving

The causal perturbation theory is an axiomatic perturbative theory of the S-matrix. This formalism has as its essence the following axioms: causality, Lorentz invariance and asymptotic conditions. Any other property must be showed via the…

High Energy Physics - Theory · Physics 2017-09-25 R. Bufalo , B. M. Pimentel , D. E. Soto

A general non-linear response theory is derived for an arbitrary time-dependent Hamiltonian, not necessarily obeying time-reversal symmetry. This allows us to obtain a greatly generalized Kubo type formula. Applied to a mesoscopic system…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 Ines Safi

A method of solving the time-dependent Schr\"odinger equation is presented, in which a finite region of space is treated explicitly, with the boundary conditions for matching the wave-functions on to the rest of the system replaced by an…

Materials Science · Physics 2009-11-13 J. E. Inglesfield

The quantum electrodynamics in presence of background external fields is developed. Modern methods of local quantum physics allow to formulate the theory on arbitrarily strong possibly time-dependent external fields. Non-linear observables…

High Energy Physics - Theory · Physics 2009-09-29 P. Marecki

We review the structure of the conservation laws in noninteracting spin chains and unveil a formal expression for the corresponding currents. We briefly discuss how interactions affect the picture. In the second part, we explore the effects…

Statistical Mechanics · Physics 2016-12-22 Maurizio Fagotti

Ever since Schrodinger, Time in quantum theory is postulated Newtonian for every reference frame. With the help of certain known mathematical results, we show that the concept of the so-called Local Time allows avoiding the postulate. In…

Quantum Physics · Physics 2016-10-26 H. Kitada , J. Jeknic-Dugic , M. Arsenijevic , M. Dugic

Recently, variational quantum metrology was proposed for Hamiltonians with multiplicative parameters, wherein the estimation precision can be optimized via variational circuits. However, systems with generic Hamiltonians still lack these…

Quantum Physics · Physics 2023-09-25 Le Bin Ho

Landau-Zener tunneling (LZT) is a fundamental dynamical phenomenon, ubiquitous in various quantum systems. Here, we propose a time-varying electric circuit to address the question of whether the quantum LZT can occur in classical systems.…

Mesoscale and Nanoscale Physics · Physics 2026-01-13 Enhong Cheng , Zheng Lian , Zezhou Chen , Li-Jun Lang

We propose a new calculation of the DC conductance of a 1-dimensional electron system described by the Luttinger model. Our approach is based on the ideas of Landauer and B\"{u}ttiker and on the methods of current algebra. We analyse in…

Condensed Matter · Physics 2016-08-15 Anton Yu. Alekseev , Vadim V. Cheianov , Jürg Fröhlich

We argue that correct account of the quantum properties of macroscopic objects which form reference frames (RF) demand the change of the standard space-time picture accepted in Quantum Mechanics. Galilean or Lorentz space-time…

High Energy Physics - Theory · Physics 2007-05-23 S. N. Mayburov

We study the action of time dependent canonical and coordinate transformations in phase space quantum mechanics. We extend the covariant formulation of the theory by providing a formalism that is fully invariant under both standard and time…

High Energy Physics - Theory · Physics 2014-11-18 Nuno Costa Dias , Joao Nuno Prata

We consider the algebra associated to a group of transformations which are symmetries of a regular mechanical system (i.e. system free of constraints). For time dependent coordinate transformations we show that a central extension may…

Quantum Physics · Physics 2007-05-23 A. Cabo , J. L. Lucio M. , V. Villanueva