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We develop an SU(2)-invariant approach to the depolarization of quantum systems as the effect of random unitary SU(2) transformations. From it we derive an SU(2)-invariant Markovian master equation. This is applied to several quantum states…

Quantum Physics · Physics 2013-11-27 Ángel Rivas , Alfredo Luis

In fundamental theories that accounts for quantum gravitational effects, the spacetime causal structure is expected to be quantum uncertain. Previous studies of quantum causal structure focused on finite-dimensional systems. Here we present…

Quantum Physics · Physics 2019-02-18 Ding Jia

The problem of formulating a manifest covariant Hamiltonian theory of General Relativity in the presence of source fields is addressed, by extending the so-called "DeDonder-Weyl" formalism to the treatment of classical fields in curved…

General Relativity and Quantum Cosmology · Physics 2016-09-16 Claudio Cremaschini , Massimo Tessarotto

The concept of a random Lagrangian is proposed. It is considered as a basis for a new view of the old problems such as renormalization, nonzero vacuum energy and the anthropic principle. It gives rise to nontrivial consequences both in…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. G. Rubin

The expected indefinite causal structure in quantum gravity poses a challenge to the notion of entanglement: If two parties are in an indefinite causal relation of being spacelike and timelike, can they still be entangled? If so, how does…

Quantum Physics · Physics 2018-02-27 Ding Jia

Gauge theory underpins the quantum field theories of the standard model, and in a previous paper was shown via a geometric approach to describe classical electromagnetism in a form which approximates QED. Here we formalize and generalize…

General Physics · Physics 2024-10-03 Adam Marsh

Using the wave equation as an example, it is shown how to extend the hydrodynamic Lagrangian-picture method of constructing field evolution using a continuum of trajectories to second-order theories. The wave equation is represented through…

Fluid Dynamics · Physics 2015-05-28 Peter Holland

The relation between the distribution of work performed on a classical system by an external force switched on an arbitrary timescale, and the corresponding equilibrium free energy difference, is generalized to quantum systems. Using the…

Statistical Mechanics · Physics 2007-05-23 Shaul Mukamel

We derive a mean-field model that is based on a two-component Pauli-like equation and incorporates quantum, spin, and relativistic effects up to second order in $1/c$. Using a Lagrangian approach, we obtain the self-consistent charge and…

Quantum Physics · Physics 2014-03-18 Anant Dixit , Yannick Hinschberger , Jens Zamanian , Giovanni Manfredi

Because scaling symmetries of the Euler-Lagrange equations are generally not variational symmetries of the action, they do not lead to conservation laws. Instead, an extension of Noether's theorem reduces the equations of motion to…

Classical Physics · Physics 2016-11-25 Sidney Bludman , Dallas C. Kennedy

It is univocally anticipated that in a theory of quantum gravity, there exist quantum superpositions of semiclassical states of spacetime geometry. Such states could arise for example, from a source mass in a superposition of spatial…

General Relativity and Quantum Cosmology · Physics 2025-01-20 Joshua Foo , Robert B. Mann , Magdalena Zych

A system of equations, describing the evolution of electromagnetic fields, is introduced and discussed. The model is strictly related to Maxwell's equations. As a matter of fact, the Lagrangian is the same, but the variations are subjected…

General Physics · Physics 2010-08-13 Daniele Funaro

We develop a method for systematically constructing Lagrangian functions for dissipative mechanical, electrical and, mechatronic systems. We derive the equations of motion for some typical mechatronic systems using deterministic principles…

Classical Physics · Physics 2012-11-20 A. Allison , C. E. M. Pearce , D. Abbott

The one-dimensional shallow water equations in Eulerian and Lagrangian coordinates are considered. It is shown the relationship between symmetries and conservation laws in Lagrangian (potential) coordinates and symmetries and conservation…

Mathematical Physics · Physics 2020-06-24 V. A. Dorodnitsyn , E. I. Kaptsov

This note presents an attempt to provide a conceptual framework for variational formulations of classical physics. Variational principles of physics have all a common source in the {\it principle of virtual work} well known in statics of…

Mathematical Physics · Physics 2007-05-23 Wlodzimierz M. Tulczyjew

A new approach to quantum mechanics based on independence of the Continuum Hypothesis is proposed. In one-dimensional case, it is shown that the properties of the set of intermediate cardinality coincide with quantum phenomenology.

Quantum Physics · Physics 2007-05-23 O. Yaremchuk

In this paper, we survey our recent results on the variational formulation of nonequilibrium thermodynamics for the finite dimensional case of discrete systems as well as for the infinite dimensional case of continuum systems. Starting with…

Mathematical Physics · Physics 2019-04-09 François Gay-Balmaz , Hiroaki Yoshimura

We propose a system of equations to describe the interaction of a quasiclassical variable $X$ with a set of quantum variables $x$ that goes beyond the usual mean field approximation. The idea is to regard the quantum system as continuously…

Quantum Physics · Physics 2009-10-30 L. Diosi , J. J. Halliwell

In this paper, we present a variational treatment of the linear dependence for a non-orthogonal time-dependent basis set in solving the Schr\"odinger equation. The method is based on: i) the definition of a linearly independent working…

Quantum Physics · Physics 2022-10-12 Loïc Joubert-Doriol

Lagrangian contact supersymmetries (depending on derivatives of arbitrary order) are treated in very general setting. The cohomology of the variational bicomplex on an arbitrary graded manifold and the iterated cohomology of a generic…

High Energy Physics - Theory · Physics 2009-11-10 G. Giachetta , L. Mangiarotti , G. Sardanashvily
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