4,719 research outputs found
Representations and Properties of Generalized Statistics
A generalization of statistics is proposed and developed. The
generalized quantum statistics is completely specified by a set of
Jacobson generators satisfying a set of triple algebraic relations.
Fock-Hilbert representations and Bargmann-Fock realizations are derived.Comment: 12 pages, to appear in IJMPA (2006
Mass as a Relativistic Quantum Observable
A field state containing photons propagating in different directions has a
non vanishing mass which is a quantum observable. We interpret the shift of
this mass under transformations to accelerated frames as defining space-time
observables canonically conjugated to energy-momentum observables. Shifts of
quantum observables differ from the predictions of classical relativity theory
in the presence of a non vanishing spin. In particular, quantum redshift of
energy-momentum is affected by spin. Shifts of position and energy-momentum
observables however obey simple universal rules derived from invariance of
canonical commutators.Comment: 5 pages, revised versio
Arbitrary Rotation Invariant Random Matrix Ensembles and Supersymmetry
We generalize the supersymmetry method in Random Matrix Theory to arbitrary
rotation invariant ensembles. Our exact approach further extends a previous
contribution in which we constructed a supersymmetric representation for the
class of norm-dependent Random Matrix Ensembles. Here, we derive a
supersymmetric formulation under very general circumstances. A projector is
identified that provides the mapping of the probability density from ordinary
to superspace. Furthermore, it is demonstrated that setting up the theory in
Fourier superspace has considerable advantages. General and exact expressions
for the correlation functions are given. We also show how the use of hyperbolic
symmetry can be circumvented in the present context in which the non-linear
sigma model is not used. We construct exact supersymmetric integral
representations of the correlation functions for arbitrary positions of the
imaginary increments in the Green functions.Comment: 36 page
Vacuum fluctuations, accelerated motion and conformal frames
Radiation from a mirror moving in vacuum electromagnetic fields is shown to
vanish in the case of a uniformly accelerated motion. Such motions are related
to conformal coordinate transformations, which preserve correlation functions
characteristic of vacuum fluctuations. As a result, vacuum fluctuations remain
invariant under reflection upon a uniformly accelerated mirror, which therefore
does not radiate and experiences no radiation reaction force. Mechanical
effects of vacuum fluctuations thus exhibit an invariance with respect to
uniformly accelerated motions.Comment: 7 page
Evaluation of a Tetracycline-Inducible Promoter in Staphylococcus aureus In Vitro and In Vivo and Its Application in Demonstrating the Role of sigB in Microcolony Formation
An inducible promoter system provides a powerful tool for studying the genetic basis for virulence. A variety of inducible systems have been used in other organisms, including pXyl-xylR-inducible promoter, the pSpac-lacI system, and the arabinose-inducible PBAD promoter, but each of these systems has limitations in its application to Staphylococcus aureus. In this study, we demonstrated the efficacy of a tetracycline-inducible promoter system in inducing gene expression in S. aureus in vitro and inside epithelial cells as well as in an animal model of infection. Using the xyl/tetO promoter::gfpuvr fusion carried on a shuttle plasmid, we demonstrated that dose-dependant tetracycline induction, as measured by bacterial fluorescence, occurred in each of the above environments while basal activation under noninduced conditions remained low. To ascertain how the system can be used to elucidate the genetic basis of a pathogenic phenotype, we cloned the sigB gene downstream of the inducible promoter. Induction of SigB expression led to dose-dependent attachment of the tested strain to polystyrene microtiter wells. Additionally, bacterial microcolony formation, an event preceding mature biofilm formation, also increased with tetracycline induction of SigB
Indirect RKKY interaction in any dimensionality
We present an analytical method which enables one to find the exact spatial
dependence of the indirect RKKY interaction between the localized moments via
the conduction electrons for the arbitrary dimensionality . The
corresponding momentum dependence of the Lindhard function is exactly found for
any as well. Demonstrating the capability of the method we find the RKKY
interaction in a system of metallic layers weakly hybridized to each other.
Along with usual in-plane oscillations the RKKY interaction has the
sign-reversal character in a direction perpendicular to layers, thus favoring
the antiferromagnetic type of layers' stacking.Comment: 3 pages, REVTEX, accepted to Phys.Rev.
Closed form representation for a projection onto infinitely dimensional subspace spanned by Coulomb bound states
The closed form integral representation for the projection onto the subspace
spanned by bound states of the two-body Coulomb Hamiltonian is obtained. The
projection operator onto the dimensional subspace corresponding to the
-th eigenvalue in the Coulomb discrete spectrum is also represented as the
combination of Laguerre polynomials of -th and -th order. The latter
allows us to derive an analog of the Christoffel-Darboux summation formula for
the Laguerre polynomials. The representations obtained are believed to be
helpful in solving the breakup problem in a system of three charged particles
where the correct treatment of infinitely many bound states in two body
subsystems is one of the most difficult technical problems.Comment: 7 page
The Quantum Socket: Three-Dimensional Wiring for Extensible Quantum Computing
Quantum computing architectures are on the verge of scalability, a key
requirement for the implementation of a universal quantum computer. The next
stage in this quest is the realization of quantum error correction codes, which
will mitigate the impact of faulty quantum information on a quantum computer.
Architectures with ten or more quantum bits (qubits) have been realized using
trapped ions and superconducting circuits. While these implementations are
potentially scalable, true scalability will require systems engineering to
combine quantum and classical hardware. One technology demanding imminent
efforts is the realization of a suitable wiring method for the control and
measurement of a large number of qubits. In this work, we introduce an
interconnect solution for solid-state qubits: The quantum socket. The quantum
socket fully exploits the third dimension to connect classical electronics to
qubits with higher density and better performance than two-dimensional methods
based on wire bonding. The quantum socket is based on spring-mounted micro
wires the three-dimensional wires that push directly on a micro-fabricated
chip, making electrical contact. A small wire cross section (~1 mmm), nearly
non-magnetic components, and functionality at low temperatures make the quantum
socket ideal to operate solid-state qubits. The wires have a coaxial geometry
and operate over a frequency range from DC to 8 GHz, with a contact resistance
of ~150 mohm, an impedance mismatch of ~10 ohm, and minimal crosstalk. As a
proof of principle, we fabricated and used a quantum socket to measure
superconducting resonators at a temperature of ~10 mK.Comment: Main: 31 pages, 19 figs., 8 tables, 8 apps.; suppl.: 4 pages, 5 figs.
(HiRes figs. and movies on request). Submitte
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