1,117 research outputs found
Entanglement of two qubits in a relativistic orbit
The creation and destruction of entanglement between a pair of interacting
two-level detectors accelerating about diametrically opposite points of a
circular path is investigated. It is found that any non-zero acceleration has
the effect of suppressing the vacuum entanglement and enhancing the
acceleration radiation thereby reducing the entangling capacity of the
detectors. Given that for large accelerations the acceleration radiation is the
dominant effect, we investigate the evolution of a two detector system
initially prepared in a Bell state using a perturbative mater equation and
treating the vacuum fluctuations as an unobserved environment. A general
function for the concurrence is obtained for stationary and symmetric
worldlines in flatspace. The entanglement sudden death time is computed.Comment: v2: Some typo's fixed, figures compressed to smaller filesize and
added some references
Security Analysis, Agency Costs, and UK Firm Characteristics
This paper assesses the monitoring power of security analysts from the manager-shareholder conflict perspective. Using a sample of UK firms tracked by security analysts, our evidence supports the view that security analysis acts as a monitoring mechanism in reducing agency costs. We also find that security analysts are more effective in reducing agency costs for smaller and more focused firms rather than larger and more diversified firms suggesting that for larger and more complex firms security analysis is less effective. The UK findings suggest that the monitoring role of security analysts is not restricted to the U.S. capital market environment.
Quasi-normal modes for doubly rotating black holes
Based on the work of Chen, L\"u and Pope, we derive expressions for the
dimensional metric for Kerr-(A)dS black holes with two independent
rotation parameters and all others set equal to zero: . The Klein-Gordon equation is then explicitly separated on this
background. For this separation results in a radial equation coupled
to two generalized spheroidal angular equations. We then develop a full
numerical approach that utilizes the Asymptotic Iteration Method (AIM) to find
radial Quasi-Normal Modes (QNMs) of doubly rotating flat Myers-Perry black
holes for slow rotations. We also develop perturbative expansions for the
angular quantum numbers in powers of the rotation parameters up to second
order.Comment: RevTeX 4-1, various figure
The design and use of the Bioethics Consultation Form
The emergence of the ethics consultation as a means to resolve moral crises in clinical medicine has revealed the need for a worksheet that would facilitate intake and analysis. The author developed the “Bioethics Consultation Form” as an attempt to remedy this need. The form is arranged in an outline format and is a useful asset to ethics committee discussions and record keeping. The first section covers basic intake data concerning the patient's medical and personal information, advance directives, and values, as well as the values of the physician and family. After the intake section is completed with the above data, the ethics consultant then turns to the analysis section. This second section allows for (1) the discussion of conflicting values, (2) the identification of priorities, and (3) the elucidation of ethical norms relevant to the case.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43229/1/11017_2004_Article_BF00489215.pd
Loss of Spin Entanglement For Accelerated Electrons in Electric and Magnetic Fields
Using an open quantum system we calculate the time dependence of the
concurrence between two maximally entangled electron spins with one accelerated
uniformly in the presence of a constant magnetic field and the other at rest
and isolated from fields. We find at high Rindler temperature the proper time
for the entanglement to be extinguished is proportional to the inverse of the
acceleration cubed.Comment: 10 pages, 4 figures, appendix and other discussion added, fixed some
typographical errors and some references were correcte
Identification of a polymer growth process with an equilibrium multi-critical collapse phase transition: the meeting point of swollen, collapsed and crystalline polymers
We have investigated a polymer growth process on the triangular lattice where
the configurations produced are self-avoiding trails. We show that the scaling
behaviour of this process is similar to the analogous process on the square
lattice. However, while the square lattice process maps to the collapse
transition of the canonical interacting self-avoiding trail model (ISAT) on
that lattice, the process on the triangular lattice model does not map to the
canonical equilibrium model. On the other hand, we show that the collapse
transition of the canonical ISAT model on the triangular lattice behaves in a
way reminiscent of the -point of the interacting self-avoiding walk
model (ISAW), which is the standard model of polymer collapse. This implies an
unusual lattice dependency of the ISAT collapse transition in two dimensions.
By studying an extended ISAT model, we demonstrate that the growth process
maps to a multi-critical point in a larger parameter space. In this extended
parameter space the collapse phase transition may be either -point-like
(second-order) or first-order, and these two are separated by a multi-critical
point. It is this multi-critical point to which the growth process maps.
Furthermore, we provide evidence that in addition to the high-temperature
gas-like swollen polymer phase (coil) and the low-temperature liquid drop-like
collapse phase (globule) there is also a maximally dense crystal-like phase
(crystal) at low temperatures dependent on the parameter values. The
multi-critical point is the meeting point of these three phases. Our
hypothesised phase diagram resolves the mystery of the seemingly differing
behaviours of the ISAW and ISAT models in two dimensions as well as the
behaviour of the trail growth process
Scalar spheroidal harmonics in five dimensional Kerr-(A)dS
We derive expressions for the general five-dimensional metric for Kerr-(A)dS
black holes. The Klein-Gordon equation is explicitly separated and we show that
the angular part of the wave equation leads to just one spheroidal wave
equation, which is also that for charged five-dimensional Kerr-(A)dS black
holes. We present results for the perturbative expansion of the angular
eigenvalue in powers of the rotation parameters up to 6th order and compare
numerically with the continued fraction method.Comment: 11 pages, two figures, one table; vz. 2: reference added and grammar
correcte
How men view genetic testing for prostate cancer risk: findings from focus groups
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65567/1/j.1399-0004.2000.580303.x.pd
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