scholarly journals GROUND STATE OF THE MASSLESS NELSON MODEL WITHOUT INFRARED CUTOFF IN A NON-FOCK REPRESENTATION

2001 ◽  
Vol 13 (09) ◽  
pp. 1075-1094 ◽  
Author(s):  
ASAO ARAI
Keyword(s):  
Scalar Field ◽  
Ground State ◽  
Coupling Constant ◽  
Fock Representation ◽  
Nelson Model ◽  
Canonical Commutation Relations ◽  
Commutation Relations ◽  
Quantum Particles ◽  
Infrared Cutoff ◽  
Massless Quantum

We consider a model of quantum particles coupled to a massless quantum scalar field, called the massless Nelson model, in a non-Fock representation of the time-zero fields which satisfy the canonical commutation relations. We show that the model has a ground state for all values of the coupling constant even in the case where no infrared cutoff is made. The non-Fock representation used is inequivalent to the Fock one if no infrared cutoff is made.

scholarly journals Singular Bogoliubov transformations and inequivalent representations of canonical commutation relations

2019 ◽  
Vol 31 (08) ◽  
pp. 1950026 ◽  
Author(s):  
Asao Arai
Keyword(s):  
Fock Space ◽  
Sufficient Conditions ◽  
Bogoliubov Transformation ◽  
Fock Representation ◽  
Canonical Commutation Relations ◽  
Commutation Relations ◽  
Direct Sum ◽  
Boson Fock Space ◽  
Inequivalent Representations ◽  
Bogoliubov Transformations

We introduce a concept of singular Bogoliubov transformation on the abstract boson Fock space and construct a representation of canonical commutation relations (CCRs) which is inequivalent to any direct sum of the Fock representation. Sufficient conditions for the representation to be irreducible are formulated. Moreover, an example of such representations of CCRs is given.

scholarly journals A family of inequivalent Weyl representations of canonical commutation relations with applications to quantum field theory

2016 ◽  
Vol 28 (04) ◽  
pp. 1650007 ◽  
Author(s):  
Asao Arai
Keyword(s):  
Field Theory ◽  
Scalar Field ◽  
Fock Space ◽  
Complex Hilbert Space ◽  
Space Region ◽  
Zero Field ◽  
Canonical Commutation Relations ◽  
Commutation Relations ◽  
Time Zero ◽  
Conjugate Momentum

We consider a family of irreducible Weyl representations of canonical commutation relations with infinite degrees of freedom on the abstract boson Fock space over a complex Hilbert space. Theorems on equivalence or inequivalence of the representations are established. As a simple application of one of these theorems, the well-known inequivalence of the time-zero field and conjugate momentum for different masses in a quantum scalar field theory is rederived with space dimension [Formula: see text] arbitrary. Also a generalization of representations of the time-zero field and conjugate momentum is presented. Comparison is made with a quantum scalar field in a bounded region in [Formula: see text]. It is shown that, in the case of a bounded space region with [Formula: see text], the representations for different masses turn out to be mutually equivalent.

L2(E*, μ)-WEYL REPRESENTATIONS

2002 ◽  
Vol 05 (04) ◽  
pp. 581-592
Author(s):  
XIAOSHAN HU ◽  
ZHIYUAN HUANG ◽  
XIANGJUN WANG
Keyword(s):  
Infinite Dimensions ◽  
Direct Construction ◽  
Fock Representation ◽  
Canonical Commutation Relations ◽  
Commutation Relations

For the canonical commutation relations in infinite dimensions, we offer an explicit direct construction of Weyl representations Wϕ generated from the Fock representation by any ϕ ∈ L2(E*, μ, R) over the Q-space (E*, μ). Moreover, we obtain that, for any ϕ, ψ ∈ L2(E*, μ,R), Wϕ+ψ and Wϕ are unitarily equivalent, proving a conjecture posed by Robinson in Ref. 2. Our construction employs Wiener–Itô decomposition of the space L2(E*, μ, R) (respectively L2(E*, μ, C)).

scholarly journals STABILITY OF GROUND STATES IN SECTORS AND ITS APPLICATION TO THE WIGNER–WEISSKOPF MODEL

2001 ◽  
Vol 13 (04) ◽  
pp. 513-528 ◽  
Author(s):  
ASAO ARAI ◽  
MASAO HIROKAWA
Keyword(s):  
Excited State ◽  
Scalar Field ◽  
Ground State ◽  
Adjoint Operator ◽  
Ground States ◽  
The Other ◽  
Coupling Constant ◽  
A Value ◽  
First Excited State ◽  
The One

We consider two kinds of stability (under a perturbation) of the ground state of a self-adjoint operator: the one is concerned with the sector to which the ground state belongs and the other is about the uniqueness of the ground state. As an application to the Wigner–Weisskopf model which describes one mode fermion coupled to a quantum scalar field, we prove in the massive case the following: (a) For a value of the coupling constant, the Wigner–Weisskopf model has degenerate ground states; (b) for a value of the coupling constant, the Wigner–Weisskopf model has a first excited state with energy level below the bottom of the essential spectrum. These phenomena are nonperturbative.

scholarly journals New Affine Coherent States Based on Elements of Nonrenormalizable Scalar Field Models

2010 ◽  
Vol 2010 ◽  
pp. 1-16 ◽  
Author(s):  
John R. Klauder
Keyword(s):  
Scalar Field ◽  
Ground State ◽  
Coherent States ◽  
Continuum Limit ◽  
Quantum Fields ◽  
Commutation Relations ◽  
Scalar Field Models ◽  
Scalar Quantum ◽  
Definition Of ◽  
The Continuum

Recent proposals for a nontrivial quantization of covariant, nonrenormalizable, self-interacting, scalar quantum fields have emphasized the importance of quantum fields that obey affine commutation relations rather than canonical commutation relations. When formulated on a spacetime lattice, such models have a lattice version of the associated ground state, and this vector is used as the fiducial vector for the definition of the associated affine coherent states, thus ensuring that in the continuum limit, the affine field operators are compatible with the system Hamiltonian. In this article, we define and analyze the associated affine coherent states as well as briefly review the author's approach to nontrivial formulations of such nonrenormalizable models.

scholarly journals Linear Energy Density and the Flux of an Electric Field in Proca Tubes

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 640
Author(s):  
Vladimir Dzhunushaliev ◽  
Vladimir Folomeev ◽  
Abylaikhan Tlemisov
Keyword(s):  
Scalar Field ◽  
Electric Field ◽  
Higgs Field ◽  
Meissner Effect ◽  
Coupling Constant ◽  
Cylindrically Symmetric ◽  
Integral Characteristics ◽  
Energy And Momentum ◽  
Energy And Momentum Densities ◽  
Higgs Scalar

In this work, we study cylindrically symmetric solutions within SU(3) non-Abelian Proca theory coupled to a Higgs scalar field. The solutions describe tubes containing either the flux of a color electric field or the energy flux and momentum. It is shown that the existence of such tubes depends crucially on the presence of the Higgs field (there are no such solutions without this field). We examine the dependence of the integral characteristics (linear energy and momentum densities) on the values of the electromagnetic potentials at the center of the tube, as well as on the values of the coupling constant of the Higgs scalar field. The solutions obtained are topologically trivial and demonstrate the dual Meissner effect: the electric field is pushed out by the Higgs scalar field.

scholarly journals Noisy effects in interferometric quantum gravity tests

2017 ◽  
Vol 15 (08) ◽  
pp. 1740014 ◽  
Author(s):  
F. Benatti ◽  
R. Floreanini ◽  
S. Olivares ◽  
E. Sindici
Keyword(s):  
Quantum Gravity ◽  
Weak Coupling ◽  
Scale Effects ◽  
External Environment ◽  
Planck Scale ◽  
Canonical Commutation Relations ◽  
Commutation Relations ◽  
Photon Propagation ◽  
Gravity Theories ◽  
Planck Scale Effects

Quantum-enhanced metrology is boosting interferometer sensitivities to extraordinary levels, up to the point where table-top experiments have been proposed to measure Planck-scale effects predicted by quantum gravity theories. In setups involving multiple photon interferometers, as those for measuring the so-called holographic fluctuations, entanglement provides substantial improvements in sensitivity. Entanglement is however a fragile resource and may be endangered by decoherence phenomena. We analyze how noisy effects arising either from the weak coupling to an external environment or from the modification of the canonical commutation relations in photon propagation may affect this entanglement-enhanced gain in sensitivity.

SUPER SYMMETRY IN STRONG AND WEAK INTERACTIONS

2010 ◽  
Vol 19 (02) ◽  
pp. 263-280
Author(s):  
U. V. S. SESHAVATHARAM ◽  
S. LAKSHMINARAYANA
Keyword(s):  
Ground State ◽  
Crucial Role ◽  
Weak Interactions ◽  
Light Quark ◽  
Fermion Mass ◽  
Coupling Constant ◽  
Mass Generation ◽  
Super Symmetry ◽  
Charged Boson ◽  
Charged Mesons

For strong interaction two new fermion mass units 105.32 MeV and 11450 MeV are assumed. Existence of "Integral charge quark bosons", "Integral charge effective quark fermions", "Integral charge (effective) quark fermi-gluons" and "Integral charge quark boso-gluons" are assumed and their masses are estimated. It is noticed that, characteristic nuclear charged fermion is Xs · 105.32 = 938.8 MeV and corresponding charged boson is Xs(105.32/x) = 415.0 where Xs = 8.914 is the inverse of the strong coupling constant and x = 2.26234 is a new number by using which "super symmetry" can be seen in "strong and weak" interactions. 11450 MeV fermion and its boson of mass = 11450/x = 5060 MeV plays a crucial role in "sub quark physics" and "weak interaction". 938.8 MeV strong fermion seems to be the proton. 415 MeV strong boson seems to be the mother of the presently believed 493,496 and 547 MeV etc, strange mesons. With 11450 MeV fermion "effective quark-fermi-gluons" and with 5060 MeV boson "quark boso-gluon masses" are estimated. "Effective quark fermi-gluons" plays a crucial role in ground state charged baryons mass generation. Light quark bosons couple with these charged baryons to form doublets and triplets. "Quark boso-gluons" plays a crucial role in ground state neutral and charged mesons mass generation. Fine and super-fine rotational levels can be given by [I or (I/2)] power(1/4) and [I or (I/2)] power(1/12) respectively. Here, I = n(n+1) and n = 1, 2, 3, ….

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