1,379 research outputs found
Quantum Langevin theory of excess noise
In an earlier work [P. J. Bardroff and S. Stenholm], we have derived a fully
quantum mechanical description of excess noise in strongly damped lasers. This
theory is used here to derive the corresponding quantum Langevin equations.
Taking the semi-classical limit of these we are able to regain the starting
point of Siegman's treatment of excess noise [Phys. Rev. A 39, 1253 (1989)].
Our results essentially constitute a quantum derivation of his theory and allow
some generalizations.Comment: 9 pages, 0 figures, revte
Using smartphone-based ecological momentary assessment and personalized feedback for patients with chronic cancer-related fatigue:A proof-of-concept study
Introduction Chronic cancer-related fatigue (CCRF) is a complex multidimensional problem warranting person-centered care. Providing patients and therapists personalized feedback based on network analysis applied to ecological momentary assessment (EMA) data could facilitate case conceptualization in psycho-oncological care. The aim was to explore patients' and therapists' experiences of using an EMA app and personalized feedback based on network theory to aid case conceptualization in psycho-oncological care. Methods A n = 5 proof-of-concept study was implemented in routine psycho-oncological care. We purposively selected adult cancer patients suffering from severe CCRF who were on the waitlist for psycho-oncological care. During a 3-week period participants filled out the EMA app Energy InSight (fatigue, mood, activity, responding, and context) five times a day. Participants received a descriptive and network feedback report, which they reflected upon during the first therapy sessions. Thematic analysis was used to analyze user experiences. Results Patients experienced that filling out the Energy InSight app, as well as receiving descriptive and network-based personalized feedback provided them with insight into their CCRF. Although therapists experienced the discussion of network feedback as challenging, it facilitated the case conceptualization. Discussion Using EMA during waitlist for psychological care seemed feasible. Patients experienced beneficial effects from filling out the EMA app and talking over the personalized feedback reports, which in turn aided case conceptualization and personalized care. Based on this evaluation, an improved version of the Energy InSight app and a therapist training for providing network feedback is developed for implementation in psycho-oncological care
What seems attractive may not always work well: Evaluative and cardiovascular responses to morality and competence levels in decision-making teams
People are particularly attracted to groups that value morality. However, in social and work life, team decision-making sometimes involves balancing moral considerations with achievement goals in ambiguous situations. We examined how the importance attached to morality and competence in experimentally created task teams influenced perceived team attractiveness and motivational responses. Results showed that team attractiveness was fully determined by value attached to morality in a team. However, cardiovascular responses revealed that when actually engaging in a team interaction where unanimous decisions had to be made about competing considerations, value attached to both morality and competence in a team influenced participants’ motivational states. Congruence between the value attached to morality and competence elicited adaptive challenge responses, while incongruence between these team features elicited maladaptive threat. These results have important theoretical and practical implications.Social decision makin
On the existence of a Bose Metal at T=0
This paper aims to justify, at a microscopic level, the existence of a
two-dimensional Bose metal, i.e. a metallic phase made out of Cooper pairs at
T=0. To this end, we consider the physics of quantum phase fluctuations in
(granular) superconductors in the absence of disorder and emphasise the role of
two order parameters in the problem, viz. phase order and charge order. We
focus on the 2-d Bose Hubbard model in the limit of very large fillings, i.e. a
2-d array of Josephson junctions. We find that the algebra of phase
fluctuations is that of the Euclidean group in this limit, and show
that the model is equivalent to two coupled XY models in (2+1)-d, one
corresponding to the phase degrees of freedom, and the other the charge degrees
of freedom. The Bose metal, then, is the phase in which both these degrees of
freedom are disordered(as a result of quantum frustration). We analyse the
model in terms of its topological excitations and suggest that there is a
strong indication that this state represents a surface of critical points, akin
to the gapless spin liquid states. We find a remarkable consistency of this
scenario with certain low-T_c thin film experiments.Comment: 16 pages, 2 figure
Maxwell-Bloch approach to excess quantum noise
Quantum Matter and Optic
The Myanmar dairy sector : a quickscan of opportunities
This report describes the Myanmar dairy sector and opportunities for development, for private as well as public actors. It describes the dairy market, dairy farming systems, and the enabling environment for dairy. A number of business opportunities are listed. It concludes with recommendations on dairy clusters, dairy strategy development , and capacity development activities
Quantum statistics of overlapping modes in open resonators
We study the quantum dynamics of optical fields in weakly confining
resonators with overlapping modes. Employing a recently developed quantization
scheme involving a discrete set of resonator modes and continua of external
modes we derive Langevin equations and a master equation for the resonator
modes. Langevin dynamics and the master equation are proved to be equivalent in
the Markovian limit. Our open-resonator dynamics may be used as a starting
point for a quantum theory of random lasers.Comment: 6 pages, corrected typo
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