scholarly journals Nonseparable CCR algebras

2021 ◽  
Author(s):  
Ilijas Farah ◽  
Najla Manhal
Keyword(s):  
Canonical Commutation Relations ◽  
Noncommutative Tori ◽  
Commutation Relations ◽  
C Algebras ◽  
Infinite Type

Extending a result of the first author and Katsura, we prove that for every UHF algebra [Formula: see text] of infinite type, in every uncountable cardinality [Formula: see text] there are [Formula: see text] nonisomorphic approximately matricial C*-algebras with the same [Formula: see text] group as [Formula: see text]. These algebras are group C*-algebras “twisted” by prescribed canonical commutation relations (CCR), and they can also be considered as nonseparable generalizations of noncommutative tori.

scholarly journals FULL REGULARITY FOR A C*-ALGEBRA OF THE CANONICAL COMMUTATION RELATIONS

2009 ◽  
Vol 21 (05) ◽  
pp. 587-613 ◽  
Author(s):  
HENDRIK GRUNDLING ◽  
KARL-HERMANN NEEB
Keyword(s):  
Regular Representation ◽  
Symplectic Space ◽  
Direct Integral ◽  
Canonical Commutation Relations ◽  
C Algebra ◽  
Commutation Relations ◽  
C Algebras ◽  
Regular Representations ◽  
Direct Integral Decomposition ◽  
Integral Decomposition

The Weyl algebra — the usual C*-algebra employed to model the canonical commutation relations (CCRs), has a well-known defect, in that it has a large number of representations which are not regular and these cannot model physical fields. Here, we construct explicitly a C*-algebra which can reproduce the CCRs of a countably dimensional symplectic space (S, B) and such that its representation set is exactly the full set of regular representations of the CCRs. This construction uses Blackadar's version of infinite tensor products of nonunital C*-algebras, and it produces a "host algebra" (i.e. a generalized group algebra, explained below) for the σ-representation theory of the Abelian group S where σ(·,·) ≔ eiB(·,·)/2. As an easy application, it then follows that for every regular representation of [Formula: see text] on a separable Hilbert space, there is a direct integral decomposition of it into irreducible regular representations (a known result).

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 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.

scholarly journals Deformation of the Wheeler–DeWitt equation

2014 ◽  
Vol 29 (20) ◽  
pp. 1450106 ◽  
Author(s):  
Mir Faizal
Keyword(s):  
Commutation Relation ◽  
Canonical Commutation Relation ◽  
Big Bang ◽  
Minimum Length ◽  
Second Quantization ◽  
Canonical Commutation Relations ◽  
Commutation Relations ◽  
The Big Bang ◽  
Big Bang Singularity ◽  
Modified Theory

In this paper, we will analyze the consequences of deforming the canonical commutation relations consistent with the existence of a minimum length and a maximum momentum. We first generalize the deformation of first quantized canonical commutation relation to second quantized canonical commutation relation. Thus, we arrive at a modified version of second quantization. A modified Wheeler–DeWitt equation will be constructed by using this deformed second quantized canonical commutation relation. Finally, we demonstrate that in this modified theory the big bang singularity gets naturally avoided.

scholarly journals SUPERSYMMETRIC CANONICAL COMMUTATION RELATIONS

2006 ◽  
Vol 21 (13n14) ◽  
pp. 2937-2951 ◽  
Author(s):  
FLORIN CONSTANTINESCU
Keyword(s):  
Vector Fields ◽  
Canonical Quantization ◽  
Canonical Commutation Relations ◽  
Commutation Relations

We discuss the unitarily-represented supersymmetric canonical commutation relations which are subsequently used to canonically quantize massive and massless chiral, antichiral and vector fields. The canonical quantization shows some new facets which do not appear in the nonsupersymmetric case. Our tool is the supersymmetric positivity generating the Hilbert–Krein structure of the N = 1 superspace.

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