Quantum discord bounds the amount of distributed entanglement

The ability to distribute quantum entanglement is a prerequisite for many fundamental tests of quantum theory and numerous quantum information protocols. Two distant parties can increase the amount of entanglement between them by means of quantum communication encoded in a carrier that is sent from one party to the other. Intriguingly, entanglement can be increased even when the exchanged carrier is not entangled with the parties. However, in light of the defining property of entanglement stating that it cannot increase under classical communication, the carrier must be quantum. Here we show that, in general, the increase of relative entropy of entanglement between two remote parties is bounded by the amount of non-classical correlations of the carrier with the parties as quantified by the relative entropy of discord. We study implications of this bound, provide new examples of entanglement distribution via unentangled states and put further limits on this phenomenon.Comment: 8 pages, 1 figure, RevTeX4; Accepted for publication in Phys. Rev. Let

Characterizing quantum dynamics with initial system-environment correlations

We fully characterize the reduced dynamics of an open quantum system initially correlated with its environment. Using a photonic qubit coupled to a simulated environment we tomographically reconstruct a superchannel---a generalised channel that treats preparation procedures as inputs---from measurement of the system alone, despite its coupling to the environment. We introduce novel quantitative measures for determining the strength of initial correlations, and to allow an experiment to be optimised in regards to its environment.Comment: 10 pages, 15 figure

A rare case of retroperitoneal leiomyosarcoma

Leiomyosarcoma, a rare malignancy of smooth muscle may arise from the retroperitoneum. They often reach a large size before diagnosis is made. Patient presents with vague symptoms, as such retroperitoneal malignancies are related to displacement of organs and obstructive phenomenon. The present paper is one of the very few case reports of retroperitoneal leiomyosarcoma which illustrates the presenting symptoms, gross and microscopic findings, treatment modalities and prognostic indicators of a 70 years old male seen at Government medical college, New Civil Hospital, Surat

Work and Quantum Phase Transitions: Is there Quantum Latency?

We study the physics of quantum phase transitions from the perspective of non-equilibrium thermodynamics. For first order quantum phase transitions, we find that the average work done per quench in crossing the critical point is discontinuous. This leads us to introduce the quantum latent work in analogy with the classical latent heat of first order classical phase transitions. For second order quantum phase transitions the irreversible work is closely related to the fidelity susceptibility for weak sudden quenches of the system Hamiltonian. We demonstrate our ideas with numerical simulations of first, second, and infinite order phase transitions in various spin chain models.Comment: accepted in PR

Physician Executive Leadership: Assessing a Student-Led Approach to Healthcare Leadership Education in Medical School

Poster presented at: 14th Annual AMA Research Symposium in Orlando, Fl Objective: To investigate the effectiveness of Physican Leadership, an open access, student-led healthcare leadership program at Sidney Kimmel Medical College, in preparing to face five key emerging topics in medical practice: healthcare economics, health policy, care and quality and safety, law and medicine, and patient experience. The Problem: Gaps in Medical Education Healthcare in the US continues to evolve, and topics such as health policy, health finance, and patient experience are not central to the practice of medicine. However, the sheer volume of material students are required to learn in the preclinical years makes it challenging to introduce new subjects into traditional medical school curricula. As a result, these topics in healthcare leadership are often left out. Indeed, only 40-50% of medical student report appropriate training in the practice of medicine, including subjects as medical economics, healthcare systems, and managed care.https://jdc.jefferson.edu/pel/1002/thumbnail.jp

Measuring quantumness via anticommutators

We introduce a method to witness the quantumness of a system. The method relies on the fact that the anticommutator of two classical states is always positive. We show that there is always a nonpositive anticommutator due to any two quantum states. We notice that interference depends on the trace of the anticommutator of two states and it is therefore more natural to detect quantumness by looking at anticommutators of states rather than their commutators.Comment: 7 pages, 2 figure

How state preparation can affect a quantum experiment: Quantum process tomography for open systems

We study the effects of preparation of input states in a quantum tomography experiment. We show that maps arising from a quantum process tomography experiment (called process maps) differ from the well know dynamical maps. The difference between the two is due to the preparation procedure that is necessary for any quantum experiment. We study two preparation procedures, stochastic preparation and preparation by measurements. The stochastic preparation procedure yields process maps that are linear, while the preparations using von Neumann measurements lead to non-linear processes, and can only be consistently described by a bi-linear process map. A new process tomography recipe is derived for preparation by measurement for qubits. The difference between the two methods is analyzed in terms of a quantum process tomography experiment. A verification protocol is proposed to differentiate between linear processes and bi-linear processes. We also emphasize the preparation procedure will have a non-trivial effect for any quantum experiment in which the system of interest interacts with its environment.Comment: 13 pages, no figures, submitted to Phys. Rev.

Dissipative dynamics of quantum discord under quantum chaotic environment

We investigate the dissipative dynamics of quantum discord in a decoherence model with two initially entangled qubits in addition to a quantum kicked top. The two qubits are uncoupled during the period of our study and one of them interacts with the quantum kicked top. We find that the long time behavior of quantum discord could be well described by the fidelity decay of the quantum kicked top; for short time behavior, however, the phase of the amplitude of the fidelity decay is necessary to provide more specific information about the system. We have made comparison between the quantum kicked top and multi-mode oscillator system in describing environment, and also compared the dynamics of the entanglement with that of quantum discord.Comment: 5 pages, 3 figures, and Accepted by Europhysics Letter