366 research outputs found
Spectral distances on doubled Moyal plane using Dirac eigen-spinors
We present here a novel method of computing spectral distances in doubled
Moyal plane in a noncommutative geometrical framework using Dirac
eigen-spinors, while solving the Lipschitz ball condition explicitly through
matrices. The standard results of longitudinal, transverse and hypotenuse
distances between different pairs of pure states have been computed and
Pythagorean equality between them have been re-produced. The issue of
non-unital nature of Moyal plane algebra is taken care of through a sequence of
projection operators constructed from Dirac eigen-spinors, which plays a
crucial role throughout this paper. At the end, a toy model of "Higgs field"
has been constructed by fluctuating the Dirac operator and the variation on the
transverse distance has been demonstrated, through an explicit computation
Twisted Galilean symmetry and the Pauli principle at low energies
We show the twisted Galilean invariance of the noncommutative parameter, even
in presence of space-time noncommutativity. We then obtain the deformed algebra
of the Schr\"odinger field in configuration and momentum space by studying the
action of the twisted Galilean group on the non-relativistic limit of the
Klein-Gordon field. Using this deformed algebra we compute the two particle
correlation function to study the possible extent to which the previously
proposed violation of the Pauli principle may impact at low energies. It is
concluded that any possible effect is probably well beyond detection at current
energies.Comment: 16 pages Latex, 2 figures Some modifications made in the abstract,
introduction, typographical errors correcte
Dual families of non-commutative quantum systems
We demonstrate how a one parameter family of interacting non-commuting
Hamiltonians, which are physically equivalent, can be constructed in
non-commutative quantum mechanics. This construction is carried out exactly (to
all orders in the non-commutative parameter) and analytically in two dimensions
for a free particle and a harmonic oscillator moving in a constant magnetic
field. We discuss the significance of the Seiberg-Witten map in this context.
It is shown for the harmonic oscillator potential that an approximate duality,
valid in the low energy sector, can be constructed between the interacting
commutative and a non-interacting non-commutative Hamiltonian. This
approximation holds to order 1/B and is therefore valid in the case of strong
magnetic fields and weak Landau-level mixing.Comment: 11 pages, no figure
Seiberg-Witten map and Galilean symmetry violation in a non-commutative planar system
An effective U(1) gauge invariant theory is constructed for a non-commutative
Schrodinger field coupled to a background U(1)_{\star} gauge field in
2+1-dimensions using first order Seiberg-Witten map. We show that this
effective theory can be cast in the form of usual Schrodinger action with
interaction terms of noncommutative origin provided the gauge field is of
``background'' type with constant magnetic field. The Galilean symmetry is
investigated and a violation is found in the boost sector. We also consider the
problem of Hall conductivity in this framework.Comment: REVTeX, 4 pages, Title changed, Paper shortened, Appendix removed, A
new section on Galilean symmetry adde
Thermal effective potential in two- and three- dimensional non-commutative spaces
Thermal correlation functions and the associated effective statistical
potential are computed in two- and three-dimensional non-commutative space
using an operator formulation that makes no reference to a star product. The
corresponding results for the Moyal and Voros star products are then easily
obtained by taking the corresponding overlap with Moyal and Voros bases. The
forms of the correlation function and the effective potential are found to be
the same, except that in the Voros case the thermal length undergoes a
non-commutative deformation, ensuring that it has a lower bound of the order of
. It is shown that in a suitable basis (called here
quasi-commutative) in the multi-particle sector the thermal correlation
function coincides with the commutative result both in the Moyal and Voros
cases, with an appropriate non-commutative correction to the thermal length in
the Voros case, and that the Pauli principle is restored.Comment: 31 pages, 7 figure
On the role of twisted statistics in the noncommutative degenerate electron gas
We consider the problem of a degenerate electron gas in the background of a
uniformly distributed positive charge, ensuring overall neutrality of the
system, in the presence of non-commutativity. In contrast to previous
calculations that did not include twisted statistics, we find corrections to
the ground state energy already at first order in perturbation theory when the
twisted statistics is taken into account. These corrections arise since the
interaction energy is sensitive to two particle correlations, which are
modified for twisted anti-commutation relations
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