14,281 research outputs found
Dynamic projection on Feshbach molecules: a probe of pairing and phase fluctuations
We describe and justify a simple model for the dynamics associated with rapid
sweeps across a Feshbach resonance, from the atomic to the molecular side, in
an ultra cold Fermi system. The model allows us to relate the observed molecule
momentum distribution, including its dependence on the sweep rate, to
equilibrium properties of the initial state. For initial state near resonance,
we find that phase fluctuations sharply reduce the observed condensate
fraction. Moreover, for very fast sweeps and low temperatures, we predict a
surprising nonmonotonic dependence of the molecule condensate fraction on
detuning, that is a direct signature of quantum phase fluctuations. The
dependence of the total molecule number on sweep rate is found to be a
sensitive probe of pairing in the initial state, whether condensed or not.
Hence it can be utilized to establish the presence of a phase fluctuation
induced `psuedogap' phase in these systems.Comment: Added reference
Career progress and career barriers: Women MBA graduates in Canada and the UK
This article explores the career progress of female MBA graduates in Canada and the UK and the nature of career barriers experienced in each context. Results suggest that while Canadian women have similar career profiles to men, women in the UK lag behind their male counterparts after graduation from the course. At the same time, UK women encounter more intractable career barriers in the form of negative attitudes and prejudice. A model of the ‘MBA effect’ is proposed in terms of how the qualification may impact on career barriers. This incorporates three different types of barriers which are seen to operate at the individual level (person centred barriers) and at the intermediate/organizational level (organizational culture and attitudes, corporate practices) as well as, at the macro level, the impact of legislative frameworks. Results from the UK and Canadian surveys are discussed in relation to this model and in the context of feminist theory and women in management literature
Scale as a Transaction Cost Variable in the U.S. Biopower Industry
With increasing interest in renewable energy from agriculture, including biopower and cellulose ethanol, several aspects of the industry must be understood. Study of the organization of the biopower industry represents an under researched area and a new application of transaction cost theory to an emerging industry. Refinement of the theory can also result from challenging applications. This article provides an application of transaction cost economics to the existing United States biopower industry while challenging the empirical convention of excluding production cost variables from transaction cost analysis. Utilizing survey data from 53 biopower generators, scale is modeled as a transaction cost variable in explaining the choice of organizational from. Consistent with transaction cost theory, the probability of observing internal organization is found to be negatively correlated to scale. Given this evidence, this article reconsiders the impact of scale and transaction costs on the choice of organizational from.Resource /Energy Economics and Policy,
Quench dynamics and non equilibrium phase diagram of the Bose-Hubbard model
We investigate the time evolution of correlations in the Bose-Hubbard model
following a quench from the superfluid to the Mott insulating phase. For large
values of the final interaction strength the system approaches a distinctly
non-equilibrium steady state that bears strong memory of the initial
conditions. In contrast, when the final interaction strength is comparable to
the hopping, the correlations are rather well approximated by those at thermal
equilibrium. The existence of two distinct non-equilibrium regimes is
surprising given the non-integrability of the Bose-Hubbard model. We relate
this phenomena to the role of quasi-particle interactions in the Mott
insulating state
Social Security and the Low-Income Worker
Social Security is important to all Americans, but, particularly, to low-income workers and their families. Financing the program partly through earmarked deductions from employees’ wages is an integral and vital part of Social Security’s design, and has been an important reason for Social Security’s success and broad public support over the program’s seventy-year life. At the same time, these contributions are harder to bear for those with lower wages. Just as the EITC has eased the burden of these contributions without undermining the basic structure and philosophy of Social Security, so the program’s long-range deficit, if eliminated properly, can help strengthen Social Security while remaining sensitive to the burdens of the low-wage worker. If that is done, Social Security will continue, in the words of President Franklin Roosevelt, “to provide sound and adequate protection against the vicissitudes of modern life” for all workers and their families, now and in the future
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