Time-evolution and dynamical phase transitions at a critical time in a system of one dimensional bosons after a quantum quench

A renormalization group approach is used to show that a one dimensional system of bosons subject to a lattice quench exhibits a finite-time dynamical phase transition where an order parameter within a light-cone increases as a non-analytic function of time after a critical time. Such a transition is also found for a simultaneous lattice and interaction quench where the effective scaling dimension of the lattice becomes time-dependent, crucially affecting the time-evolution of the system. Explicit results are presented for the time-evolution of the boson interaction parameter and the order parameter for the dynamical transition as well as for more general quenches.Comment: final published versio

Current driven defect unbinding transition in an XY ferromagnet

A Keldysh-contour effective field theory is derived for magnetic vortices in the presence of current flow. The effect of adiabatic and non-adiabatic spin transfer torques on vortex motion is highlighted. Similarities to and differences from the superconducting case are presented and explained. Current flow across a magnetically ordered state is shown to lead to a defect-unbinding phase transition which is intrinsically nonequilibrium in the sense of not being driven by a variation in effective temperature. The dependence of the density of vortices on the current density is determined.Comment: 13 pages. Minor changes, to appear in PR

Coulomb Gas on the Keldysh Contour: Anderson-Yuval-Hamann representation of the Nonequilibrium Two Level System

The nonequilibrium tunnelling center model of a localized electronic level coupled to a fluctuating two-state system and to two electronic reservoirs, is solved via an Anderson-Yuval-Hamann mapping onto a plasma of alternating positive and negative charges time-ordered along the two "Keldysh" contours needed to describe nonequilibrium physics. The interaction between charges depends both on whether their time separation is small or large compared to a dephasing scale defined in terms of the chemical potential difference between the electronic reservoirs and on whether their time separation is larger or smaller than a decoherence scale defined in terms of the current flowing from one reservoir to another. A renormalization group transformation appropriate to the nonequilibrium problem is defined. An important feature is the presence in the model of a new coupling, essentially the decoherence rate, which acquires an additive renormalization similar to that of the energy in equilibrium problems. The method is used to study interplay between the dephasing-induced formation of independent resonances tied to the two chemical potentials and the decoherence which cuts off the scaling and leads to effectively classical long-time behavior. We determine the effect of departures from equilibrium on the localization-delocalization phase transition.Comment: discussion and references added, to appear in PR

Mode coupling induced dissipative and thermal effects at long times after a quantum quench

An interaction quench in a Luttinger liquid can drive it into an athermal steady state. We analyze the effects on such an out of equilibrium state of a mode coupling term due to a periodic potential. Employing a perturbative renormalization group approach we show that even when the periodic potential is an irrelevant perturbation in equilibrium, it has important consequences on the athermal steady state as it generates a temperature as well as a dissipation and hence a finite life-time for the bosonic modes.Comment: 4+ pages and 2 figure

Nonequilibrium dynamics in a two-channel Kondo system due to a quantum quench

Recent experiments by Potok et al. have demonstrated a remarkable tunability between a single-channel Fermi liquid fixed point and a two-channel non-Fermi liquid fixed point. Motivated by this we study the nonequilibrium dynamics due to a sudden quench of the parameters of a Hamiltonian from a single-channel to a two-channel anisotropic Kondo system. We find a distinct difference between the long time behavior of local quantities related to the impurity spin as compared to that of bulk quantities related to the total (conduction electrons + impurity) spin of the system. In particular, the local impurity spin and the local spin susceptibility are found to equilibrate, but in a very slow power-law fashion which is peculiar to the non-Fermi liquid properties of the Hamiltonian. In contrast, we find a lack of equilibration in the two particle expectation values related to the total spin of the system.Comment: 5 pages, 1 fig. Accepted in PR

Shift in HR Professionals Role: Critical Trends in HR Management Practices

The business world is concerned with the improvement of organizational performance. Consequently, Human Resource Management (HRM) practices outcome on organizational performance has been the major concern of the previous scholars. Therefore, any organization that fails to improve its performance would not be able to meet up with trends in achieving competitive advantages. HR means understanding the implications of globalization, work-force diversity, changing skill requirements, corporate downsizing, continuous improvement initiatives, re-engineering, the contingent workforce, decentralized work sites, and employee involvement. Organizations today are also witnessing a change in the system, management cultures, and philosophy due to the global alignment.There is a need for multi-skill development and the role of HRM  is becoming all the more important

Contracting for Financial Privacy: The Rights of Banks and Customers Under the Reauthorized Patriot Act

The 2001 Patriot Act chipped away financial privacy protections by allowing law enforcement authorities easier access to bank customer records. Under the Patriot Act, federal authorities may access customer records by issuing formal subpoena-like requests under the Foreign Intelligence Surveillance Act (FISA) or informal national security letters (NSLs) to banks while prohibiting notice to any affected customers. However, the 2006 revisions to the Patriot Act permit banks to challenge FISA requests and NSLs in federal court before releasing customer records. While the Act does not require banks to make these challenges on behalf of their customers, this Paper will argue that the contracts banks sign with their customers – interpreted in light of the banking tradition of confidentiality and the current regime of federal and state privacy protections – obligate banks to review government requests for customer records and file challenges when appropriate. Furthermore, I will argue that banks and customers should be able to enter into contracts explicitly obligating banks to challenge FISA requests and NSLs, and that such contracts would be enforceable and financially feasible

Somatic symptom disorder in dermatology

Somatic symptom disorder (SSD) is defined by the prominence of somatic symptoms associated with abnormal thoughts, feelings, and behaviors related to the symptoms, resulting in significant distress and impairment. Individuals with these disorders are more commonly encountered in primary care and other medical settings, including dermatology practice, than in psychiatric and other mental health settings. What defines the thoughts, feelings, and behaviors as abnormal is that they are excessive, that is, out of proportion to other patients with similar somatic symptoms, and that they result in significant distress and impairment. SSD may occur with or without the presence of a diagnosable dermatologic disorder. When a dermatologic disorder is present, SSD should be considered when the patient is worrying too much about his or her skin, spending too much time and energy on it, and especially if the patient complains of many nondermatologic symptoms in addition. The differential diagnosis includes other psychiatric disorders, including depression, anxiety disorders, delusions of parasitosis, and body dysmorphic disorder