5,177 research outputs found
Bulk and boundary factorized S-matrices
We investigate the -invariant bulk (1+1D, factorized) -matrix
constructed by Ogievetsky, using the bootstrap on the three-point coupling of
the vector multiplet to constrain its CDD ambiguity. We then construct the
corresponding boundary -matrix, demonstrating it to be consistent with
symmetry.Comment: 7 page
Quantum equilibration in finite time
It has recently been shown that small quantum subsystems generically
equilibrate, in the sense that they spend most of the time close to a fixed
equilibrium state. This relies on just two assumptions: that the state is
spread over many different energies, and that the Hamiltonian has
non-degenerate energy gaps. Given the same assumptions, it has also been shown
that closed systems equilibrate with respect to realistic measurements. We
extend these results in two important ways. First, we prove equilibration over
a finite (rather than infinite) time-interval, allowing us to bound the
equilibration time. Second, we weaken the non degenerate energy gaps condition,
showing that equilibration occurs provided that no energy gap is hugely
degenerate.Comment: 7 page
Equilibration of quantum systems and subsystems
We unify two recent results concerning equilibration in quantum theory. We
first generalise a proof of Reimann [PRL 101,190403 (2008)], that the
expectation value of 'realistic' quantum observables will equilibrate under
very general conditions, and discuss its implications for the equilibration of
quantum systems. We then use this to re-derive an independent result of Linden
et. al. [PRE 79, 061103 (2009)], showing that small subsystems generically
evolve to an approximately static equilibrium state. Finally, we consider
subspaces in which all initial states effectively equilibrate to the same
state.Comment: 5 page
Equilibration of isolated macroscopic quantum systems
We investigate the equilibration of an isolated macroscopic quantum system in
the sense that deviations from a steady state become unmeasurably small for the
overwhelming majority of times within any sufficiently large time interval. The
main requirements are that the initial state, possibly far from equilibrium,
exhibits a macroscopic population of at most one energy level and that
degeneracies of energy eigenvalues and of energy gaps (differences of energy
eigenvalues) are not of exceedingly large multiplicities. Our approach closely
follows and extends recent works by Short and Farrelly [2012 New J. Phys. 14
013063], in particular going beyond the realm of finite-dimensional systems and
large effective dimensions.Comment: 19 page
On the speed of fluctuations around thermodynamic equilibrium
We study the speed of fluctuation of a quantum system around its
thermodynamic equilibrium state, and show that the speed will be extremely
small for almost all times in typical thermodynamic cases. The setting
considered here is that of a quantum system couples to a bath, both jointly
described as a closed system. This setting, is the same as the one considered
in [N. Linden et al., Phys. Rev. E 79:061103 (2009)] and the ``thermodynamic
equilibrium state'' refers to a situation that includes the usual thermodynamic
equilibrium case, as well as far more general situations
Techniques for the realization of ultra- reliable spaceborne computer Final report
Bibliography and new techniques for use of error correction and redundancy to improve reliability of spaceborne computer
Thermodynamic entropy of a many body energy eigenstate
It is argued that a typical many body energy eigenstate has a well defined
thermodynamic entropy and that individual eigenstates possess thermodynamic
characteristics analogous to those of generic isolated systems. We examine
large systems with eigenstate energies equivalent to finite temperatures. When
quasi-static evolution of a system is adiabatic (in the quantum mechanical
sense), two coupled subsystems can transfer heat from one subsystem to another
yet remain in an energy eigenstate. To explicitly construct the entropy from
the wave function, degrees of freedom are divided into two unequal parts. It is
argued that the entanglement entropy between these two subsystems is the
thermodynamic entropy per degree of freedom for the smaller subsystem. This is
done by tracing over the larger subsystem to obtain a density matrix, and
calculating the diagonal and off-diagonal contributions to the entanglement
entropy.Comment: 18 page
An Exploratory Evaluation of a Treatment Mall at a State Psychiatric Hospital
The Treatment Mall is a model of inpatient psychosocial treatment provided to adults with severe mental illness to deliver recovery-oriented, evidenced-based treatment and has been implemented in state mental hospitals across the United States. The present study is an exploratory evaluation of a recently implemented Treatment Mall in a state mental hospital. To evaluate this program, the experiences of clients (N=28), staff (N=32), and administrators (N=5) were compiled using a quantitative questionnaire and focused on empowerment, skill development, and satisfaction. Additionally, data from the hospital database (N=183) were extracted and analyzed by comparing frequencies of occurrence 90 days before and 90 days after Treatment Mall implementation. The findings indicate that clients reported learning skills and were satisfied with how they were treated at the Treatment Mall. Female clients and staff viewed independent living and recovery possibilities significantly more positively than male clients and staff. Hospital performance indicators showed no significant changes pre to post implementation.
No evidence for killer sperm or other selective interactions between human spermatozoa in ejaculates of different males in vitro
This study examines one of the possible mechanisms of sperm competition, i.e. the kamikaze sperm hypothesis. This hypothesis states that sperm from different males interact to incapacitate each other in a variety of ways. We used ejaculates from human donors to compare mixes of semen in vitro from the same or different males. We measured the following parameters: (i) the degree of sperm aggregation, velocity and proportion of morphologically normal sperm after 1 and 3 h incubation in undiluted semen samples, (ii) the proportion of viable sperm plus the same parameters as in (i) in 'swim-up' sperm suspensions after 1 and 3 h incubation, (iii) the degree of self and non-self sperm aggregation using fluorescent dyes to distinguish the sperm of different males, and (iv) the extent of sperm capacitation and acrosome-reacted sperm in mixtures of sperm from the same and different males. We observed very few significant changes in sperm aggregation or performance in mixtures of sperm from different males compared with mixtures from the same male and none that were consistent with previously reported findings. The incapacitation of rival sperm therefore seems an unlikely mechanism of sperm competition in humans
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