scholarly journals The Semi-Classical Approximation for Modular Operads

1998 ◽  
Vol 194 (2) ◽  
pp. 481-492 ◽  
Author(s):  
E. Getzler
Keyword(s):  
Classical Approximation

scholarly journals Finite-volume form factors in semi-classical approximation

2003 ◽  
Vol 670 (3) ◽  
pp. 464-478 ◽  
Author(s):  
G. Mussardo ◽  
V. Riva ◽  
G. Sotkov
Keyword(s):  
Finite Volume ◽  
Form Factors ◽  
Volume Form ◽  
Classical Approximation

Thermodynamic properties of charged ideal spin-1 bosons in a trap under a magnetic field

2014 ◽  
Vol 28 (26) ◽  
pp. 1450206 ◽  
Author(s):  
Yushan Li
Keyword(s):  
Magnetic Field ◽  
Critical Temperature ◽  
External Magnetic Field ◽  
Thermodynamic Properties ◽  
Bose Gases ◽  
Spin Factor ◽  
Classical Approximation ◽  
Spinless Case

Thermodynamics of trapped charged ideal spin-1 bosons confined in a magnetic field are investigated within semi-classical approximation and truncated-summation approach. It is shown that the critical temperature increases slightly at the first, and then decreases slowly with increasing external magnetic field. Charged spin-1 Bose gases present a crossover from diamagnetism to paramagnetism as the spin factor increases. Charged spin-1 Bose gases exhibit distinct thermodynamic behaviors from the spinless case.

scholarly journals Asymptotically equivalent functions and ultrafilters applied to noncommutative quantum cosmology

2019 ◽  
Vol 65 (5 Sept-Oct) ◽  
pp. 519
Author(s):  
J.A. Astorga-Moreno ◽  
E.A. Mena Barboza ◽  
And M.A. García-Aspeitia
Keyword(s):  
Dynamical System ◽  
Cosmological Constant ◽  
Commutation Relation ◽  
Quantum Cosmology ◽  
Positive Cosmological Constant ◽  
Classical Approximation ◽  
Noncommutative Quantum

Using the semi-classical approximation to the Wheeler-DeWitt equation obtained via Arnowitt-Deser-Misner (ADM) formalism in the Friedmann-Lemaitre-Robertson-Walker (FLRW) model coupled to a scalar eld and positive cosmological constant, and in the Kantowski-Sachs (KS) Universe, we introduced a deformation on the commutation relation for the minisuperspace variables and find an explicit semiclassical expression equivalent, in an adequate limit, to the solution with the aid of asymptotically equal functions and the theory of Ultralters, oering a suggestive alternative to sketch the behavior of the dynamical system involved without the need to solve it numerically.

Classical approximation for transmission depolarization of a neutron beam

1966 ◽  
Vol 82 (3) ◽  
pp. 657-661 ◽  
Author(s):  
P. Nyborg ◽  
Pao Lu ◽  
R.H. Good
Keyword(s):  
Neutron Beam ◽  
Classical Approximation

scholarly journals Semi-classical approximations based on Bohmian mechanics

2020 ◽  
Vol 35 (14) ◽  
pp. 2050070 ◽  
Author(s):  
Ward Struyve
Keyword(s):  
Wave Function ◽  
Quantum Theory ◽  
Quantum Gravity ◽  
Quantum Electrodynamics ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Bohmian Mechanics ◽  
Expectation Values ◽  
Usual Approach ◽  
Classical Approximation

Semi-classical theories are approximations to quantum theory that treat some degrees of freedom classically and others quantum mechanically. In the usual approach, the quantum degrees of freedom are described by a wave function which evolves according to some Schrödinger equation with a Hamiltonian that depends on the classical degrees of freedom. The classical degrees of freedom satisfy classical equations that depend on the expectation values of quantum operators. In this paper, we study an alternative approach based on Bohmian mechanics. In Bohmian mechanics the quantum system is not only described by the wave function, but also with additional variables such as particle positions or fields. By letting the classical equations of motion depend on these variables, rather than the quantum expectation values, a semi-classical approximation is obtained that is closer to the exact quantum results than the usual approach. We discuss the Bohmian semi-classical approximation in various contexts, such as nonrelativistic quantum mechanics, quantum electrodynamics and quantum gravity. The main motivation comes from quantum gravity. The quest for a quantum theory for gravity is still going on. Therefore a semi-classical approach where gravity is treated classically may be an approximation that already captures some quantum gravitational aspects. The Bohmian semi-classical theories will be derived from the full Bohmian theories. In the case there are gauge symmetries, like in quantum electrodynamics or quantum gravity, special care is required. In order to derive a consistent semi-classical theory it will be necessary to isolate gauge-independent dependent degrees of freedom from gauge degrees of freedom and consider the approximation where some of the former are considered classical.

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