488 research outputs found
Quons as su(2) Irreducible Tensor Operators
We prove that, for the quon algebra, which interpolates between the Bose and
Fermi statistics and depends on a free parameter q,it is possible to build an
su(2) irreducible representation. One of the consequences of this fact is that
the quons couple via the same angular momentum coupling rules obeyed by
ordinary bosons and fermions.Comment: 8 pages,Late
Applications of the Quon Algebra: 3-D Harmonic Oscillator and the Rotor Model
In this work we present a method to build in a systematic way a many-body
quon basis state. In particular, we show a closed expression for a given number
N of quons, restricted to the permutational symmetric subspace, which belongs
to the whole quonic space. The method is applied to two simple problems: the
three-dimensional harmonic oscillator and the rotor model and compared to
previous quantum algebra results. The differences obtained and possible future
applications are also discussed.Comment: 13 pages, 2 figure
Quons Restricted to the Antisymmetric Subspace: Formalism and Applications
In this work we develop a formalism to treat quons restricted to the
antisymmetric part of their many-body space. A model in which a system of
identical quons interact through a pairing force is then solved within this
restriction and the differences between our solution and the usual fermionic
model solution are then presented and discussed in detail. Possible connections
to physical systems are also considered.Comment: 12 pages, 3 figure
Low-frequency measurement of the tunneling amplitude in a flux qubit
We have observed signatures of resonant tunneling in an Al three-junction
qubit, inductively coupled to a Nb LC tank circuit. The resonant properties of
the tank oscillator are sensitive to the effective susceptibility (or
inductance) of the qubit, which changes drastically as its flux states pass
through degeneracy. The tunneling amplitude is estimated from the data. We find
good agreement with the theoretical predictions in the regime of their
validity.Comment: REVTeX4, 3pp., 3 EPS figures. v2: new sample, textual clarifications.
v3: minor polishing; final, to appear in PRB Rapid
Decoherence and CPT Violation in a Stringy Model of Space-Time Foam
I discuss a model inspired from the string/brane framework, in which our
Universe is represented as a three brane, propagating in a bulk space time
punctured by D0-brane (D-particle) defects. As the D3-brane world moves in the
bulk, the D-particles cross it, and from an effective observer on D3 the
situation looks like a ``space-time foam'' with the defects ``flashing'' on and
off (``D-particle foam''). The open strings, with their ends attached on the
brane, which represent matter in this scenario, can interact with the
D-particles on the D3-brane universe in a topologically non-trivial manner,
involving splitting and capture of the strings by the D0-brane defects. Such
processes are described by logarithmic conformal field theories on the
world-sheet. Physically, they result in effective decoherence of the string
matter on the D3 brane, and as a result, of CPT Violation, but of a type that
implies an ill-defined nature of the effective CPT operator. Due to electric
charge conservation, only electrically neutral (string) matter can exhibit such
interactions with the D-particle foam. This may have unique, experimentally
detectable, consequences for electrically-neutral entangled quantum matter
states on the brane world, in particular the modification of the pertinent EPR
Correlation of neutral mesons in a meson factory.Comment: 41 pages Latex, five eps figures incorporated. Uses special macro
Lorentz-invariant CPT violation
A Lorentz-invariant CPT violation, which may be termed as long-distance CPT
violation in contrast to the familiar short-distance CPT violation, has been
recently proposed. This scheme is based on a non-local interaction vertex and
characterized by an infrared divergent form factor. We show that the Lorentz
covariant -product is consistently defined and the energy-momentum
conservation is preserved in perturbation theory if the path integral is
suitably defined for this non-local theory, although unitarity is generally
lost. It is illustrated that T violation is realized in the decay and formation
processes. It is also argued that the equality of masses and decay widths of
the particle and anti-particle is preserved if the non-local CPT violation is
incorporated either directly or as perturbation by starting with the
conventional CPT-even local Lagrangian. However, we also explicitly show that
the present non-local scheme can induce the splitting of particle and
anti-particle mass eigenvalues if one considers a more general class of
Lagrangians.Comment: 28 pages; note added in proof; version published in Eur. Phys. J. C
(2013) 73: 234
Implications of Space-Time foam for Entanglement Correlations of Neutral Kaons
The role of invariance and consequences for bipartite entanglement of
neutral (K) mesons are discussed. A relaxation of leads to a modification
of the entanglement which is known as the effect. The relaxation of
assumptions required to prove the theorem are examined within the context
of models of space-time foam. It is shown that the evasion of the EPR type
entanglement implied by (which is connected with spin statistics) is
rather elusive. Relaxation of locality (through non-commutative geometry) or
the introduction of decoherence by themselves do not lead to a destruction of
the entanglement. So far we find only one model which is based on non-critical
strings and D-particle capture and recoil that leads to a stochastic
contribution to the space-time metric and consequent change in the neutral
meson bipartite entanglement. The lack of an omega effect is demonstrated for a
class of models based on thermal like baths which are generally considered as
generic models of decoherence
Coherent States of the q--Canonical Commutation Relations
For the -deformed canonical commutation relations for in some Hilbert
space we consider representations generated from a vector
satisfying , where .
We show that such a representation exists if and only if .
Moreover, for these representations are unitarily equivalent
to the Fock representation (obtained for ). On the other hand
representations obtained for different unit vectors are disjoint. We
show that the universal C*-algebra for the relations has a largest proper,
closed, two-sided ideal. The quotient by this ideal is a natural -analogue
of the Cuntz algebra (obtained for ). We discuss the Conjecture that, for
, this analogue should, in fact, be equal to the Cuntz algebra
itself. In the limiting cases we determine all irreducible
representations of the relations, and characterize those which can be obtained
via coherent states.Comment: 19 pages, Plain Te
Spectropolarimetry of the Deep Impact target comet 9P/Tempel 1 with HiVIS
High resolution spectropolarimetry of the Deep Impact target, comet 9P/
Tempel 1, was performed during the impact event on July 4th, 2005 with the
HiVIS Spectropolarimeter and the AEOS 3.67m telescope on Haleakala, Maui. We
observed atypical polarization spectra that changed significantly in the few
hours after the impact. The polarization of scattered light as a function of
wavelength is very sensitive to the size and composition (complex refractive
index) of the scattering particles as well as the scattering geometry. As
opposed to most observations of cometary dust, which show an increase in the
linear polarization with the wavelength (at least in the visible domain and for
phase angles greater than about 30%, a red polarization spectrum) observations
of 9P/Tempel 1 at a phase angle of 41 degrees beginning 8 minutes after impact
and centered at 6:30UT showed a polarization of 4% at 650 nm falling to 3% at
950 nm. The next observation, centered an hour later showed a polarization of
7% at 650 nm falling to 2% at 950nm. This corresponds to a spectropolarimetric
gradient, or slope, of -0.9% per 1000 Angstroms 40 minutes after impact,
decreasing to a slope of -2.3% per 1000 Angstroms an hour and a half after
impact. This is an atypical blue polarization slope, which became more blue 1
hour after impact. The polarization values of 4% and 7% at 650nm are typical
for comets at this scattering angle, whereas the low polarization of 2% and 3%
at 950nm is not. We compare observations of comet 9P/Tempel 1 to that of a
typical comet, C/2004 Machholz, at a phase angle of 30 degrees which showed a
typical red slope, rising from 2% at 650nm to 3% at 950nm in two different
observations (+1.0 and +0.9% per 1000 Angstroms).Comment: Icarus Deep Impact special issue, accepted Aug 28 200
- …