707 research outputs found
Application of nonlinear deformation algebra to a physical system with P\"oschl-Teller potential
We comment on a recent paper by Chen, Liu, and Ge (J. Phys. A: Math. Gen. 31
(1998) 6473), wherein a nonlinear deformation of su(1,1) involving two
deforming functions is realized in the exactly solvable quantum-mechanical
problem with P\" oschl-Teller potential, and is used to derive the well-known
su(1,1) spectrum-generating algebra of this problem. We show that one of the
defining relations of the nonlinear algebra, presented by the authors, is only
valid in the limiting case of an infinite square well, and we determine the
correct relation in the general case. We also use it to establish the correct
link with su(1,1), as well as to provide an algebraic derivation of the
eigenfunction normalization constant.Comment: 9 pages, LaTeX, no figure
Nonlinear deformed su(2) algebras involving two deforming functions
The most common nonlinear deformations of the su(2) Lie algebra, introduced
by Polychronakos and Ro\v cek, involve a single arbitrary function of J_0 and
include the quantum algebra su_q(2) as a special case. In the present
contribution, less common nonlinear deformations of su(2), introduced by
Delbecq and Quesne and involving two deforming functions of J_0, are reviewed.
Such algebras include Witten's quadratic deformation of su(2) as a special
case. Contrary to the former deformations, for which the spectrum of J_0 is
linear as for su(2), the latter give rise to exponential spectra, a property
that has aroused much interest in connection with some physical problems.
Another interesting algebra of this type, denoted by , has two
series of (N+1)-dimensional unitary irreducible representations, where N=0, 1,
2, .... To allow the coupling of any two such representations, a generalization
of the standard Hopf axioms is proposed. The resulting algebraic structure,
referred to as a two-colour quasitriangular Hopf algebra, is described.Comment: 8 pages, LaTeX, no figures, submitted to Proc. 5th Int. Coll.
``Quantum Groups and Integrable Systems'', Prague, 20-22 June 1996 (to be
published in Czech. J. Phys.
Acceptability of temporary suspension of visiting during norovirus outbreaks:investigating patient, visitor and public opinion
Background
Noroviruses are a leading cause of outbreaks globally and the most common cause of service disruption due to ward closures. Temporary suspension of visiting (TSV) is increasingly a recommended public health measure to reduce exposure, transmission and impact during norovirus outbreaks; however, preventing patient–visitor contact may contravene the ethos of person-centred care, and public acceptability of this measure is not known.
Aim
To investigate the acceptability of TSV during norovirus outbreaks from the perspectives of patients, visitors and the wider public.
Methods
Cross-sectional survey of patients (N = 153), visitors (N = 175) and the public (N = 224) in three diverse areas in Scotland. Health Belief Model constructs were applied to understand ratings of acceptability of TSV during norovirus outbreaks, and to determine associations between these levels and various predictor variables.
Findings
The majority (84.6%) of respondents indicated that the possible benefits of TSV are greater than the possible disadvantages. Conversely, the majority (70%) of respondents disagreed that TSV ‘is wrong as it ignores people's rights to have contact with family and friends’. The majority (81.6%) of respondents agreed that TSV would be more acceptable if exceptions were made for seriously ill or dying patients. Correlational analysis demonstrated that overall acceptability was positively related to perceived severity (r = 0.65), identified benefits (r = 0.54) and implementing additional communication strategies (r = 0.60); acceptability was negatively related to potential barriers (r = −0.49).
Conclusions
There is greater service user and public support for the use of TSV than concerns around impinging upon patients' rights to have visitors. TSV should be considered as an acceptable infection control measure that could be implemented consistently during norovirus outbreaks
Dynamically enhancing qubit-oscillator interactions with anti-squeezing
The interaction strength of an oscillator to a qubit grows with the
oscillator's vacuum field fluctuations. The well known degenerate parametric
oscillator has revived interest in the regime of strongly detuned squeezing,
where its eigenstates are squeezed Fock states. Owing to these amplified field
fluctuations, it was recently proposed that squeezing this oscillator would
dynamically boost its coupling to a qubit. In a superconducting circuit
experiment, we observe a two-fold increase in the dispersive interaction
between a qubit and an oscillator at 5.5 dB of squeezing, demonstrating in-situ
dynamical control of qubit-oscillator interactions. This work initiates the
experimental coupling of oscillators of squeezed photons to qubits, and
cautiously motivates their dissemination in experimental platforms seeking
enhanced interactions.Comment: 21 pages, 15 figure
A report on the nonlinear squeezed states and their non-classical properties of a generalized isotonic oscillator
We construct nonlinear squeezed states of a generalized isotonic oscillator
potential. We demonstrate the non-existence of dual counterpart of nonlinear
squeezed states in this system. We investigate statistical properties exhibited
by the squeezed states, in particular Mandel's parameter, second-order
correlation function, photon number distributions and parameter in
detail. We also examine the quadrature and amplitude-squared squeezing effects.
Finally, we derive expression for the -parameterized quasi-probability
distribution function of these states. All these information about the system
are new to the literature.Comment: Accepted for publication in J. Phys. A: Math. Theo
Coupling a quantum dot, fermionic leads and a microwave cavity on-chip
We demonstrate a hybrid architecture consisting of a quantum dot circuit
coupled to a single mode of the electromagnetic field. We use single wall
carbon nanotube based circuits inserted in superconducting microwave cavities.
By probing the nanotube-dot using a dispersive read-out in the Coulomb blockade
and the Kondo regime, we determine an electron-photon coupling strength which
should enable circuit QED experiments with more complex quantum dot circuits.Comment: 4 pages, 4 figure
Circuit Quantum Electrodynamics with a Spin Qubit
Circuit quantum electrodynamics allows spatially separated superconducting
qubits to interact via a "quantum bus", enabling two-qubit entanglement and the
implementation of simple quantum algorithms. We combine the circuit quantum
electrodynamics architecture with spin qubits by coupling an InAs nanowire
double quantum dot to a superconducting cavity. We drive single spin rotations
using electric dipole spin resonance and demonstrate that photons trapped in
the cavity are sensitive to single spin dynamics. The hybrid quantum system
allows measurements of the spin lifetime and the observation of coherent spin
rotations. Our results demonstrate that a spin-cavity coupling strength of 1
MHz is feasible.Comment: Related papers at http://pettagroup.princeton.edu
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