Two qubits can be entangled in two distinct temperature regions

We have found that for a wide range of two-qubit Hamiltonians the canonical-ensemble thermal state is entangled in two distinct temperature regions. In most cases the ground state is entangled; however we have also found an example where the ground state is separable and there are still two regions. This demonstrates that the qualitative behavior of entanglement with temperature can be much more complicated than might otherwise have been expected; it is not simply determined by the entanglement of the ground state, even for the simple case of two qubits. Furthermore, we prove a finite bound on the number of possible entangled regions for two qubits, thus showing that arbitrarily many transitions from entanglement to separability are not possible. We also provide an elementary proof that the spectrum of the thermal state at a lower temperature majorizes that at a higher temperature, for any Hamiltonian, and use this result to show that only one entangled region is possible for the special case of Hamiltonians without magnetic fields.Comment: 6 pages, 4 figures, many new result

The Vortex Phase Qubit: Generating Arbitrary, Counter-Rotating, Coherent Superpositions in Bose-Einstein Condensates via Optical Angular Momentum Beams

We propose a scheme for generation of arbitrary coherent superposition of vortex states in Bose-Einstein condensates (BEC) using the orbital angular momentum (OAM) states of light. We devise a scheme to generate coherent superpositions of two counter-rotating OAM states of light using known experimental techniques. We show that a specially designed Raman scheme allows transfer of the optical vortex superposition state onto an initially non-rotating BEC. This creates an arbitrary and coherent superposition of a vortex and anti-vortex pair in the BEC. The ideas presented here could be extended to generate entangled vortex states, design memories for the OAM states of light, and perform other quantum information tasks. Applications to inertial sensing are also discussed.Comment: 4 pages, 4 figures, Revtex4, to be submitted to Phys. Rev. Let

The creation of large photon-number path entanglement conditioned on photodetection

Large photon-number path entanglement is an important resource for enhanced precision measurements and quantum imaging. We present a general constructive protocol to create any large photon number path-entangled state based on the conditional detection of single photons. The influence of imperfect detectors is considered and an asymptotic scaling law is derived.Comment: 6 pages, 4 figure

Endogenous lysophosphatidic acid (LPA1) receptor agonists demonstrate ligand bias between calcium and ERK signalling pathways in human lung fibroblasts

Background and Purpose Human lung fibroblasts (HLF) express high levels of the LPA1 receptor, a GPCR that responds to the endogenous lipid mediator, lysophosphatidic acid (LPA). Several molecular species or analogues of LPA exist and have been detected in biological fluids such as serum and plasma. The most widely expressed of the LPA receptor family is the LPA1 receptor, which predominantly couples to Gq/11, Gi/o and G12/13 proteins. This promiscuity of coupling raises the possibility that some of the LPA analogues may bias the LPA1 receptor towards one signalling pathway over another. Experimental Approach Here, we have explored the signalling profiles of a range of LPA analogues in HLF that endogenously express the LPA1 receptor. HLF were treated with LPA analogues and receptor activation monitored via calcium mobilization and ERK phosphorylation. Key Results These analyses demonstrated that the 16:0, 17:0, 18:2 and C18:1 LPA analogues appear to exhibit ligand bias between ERK phosphorylation and calcium mobilization when compared with 18:1 LPA, one of the most abundant forms of LPA that has been found in human plasma. Conclusion and Implications The importance of LPA as a key signalling molecule is shown by its widespread occurrence in biological fluids and its association with disease conditions such as fibrosis and cancer. These findings have important, as yet unexplored, implications for the (patho-) physiological signalling of the LPA1 receptor, as it may be influenced not only by the concentration of endogenous ligand but the isoform as well

Incidental renocolic fistula with xanthogranulomatous pyelonephritis

AbstractINTRODUCTIONWe report the case of a 66-year-old female undergoing elective nephrectomy for a non-functioning kidney in whom an incidental renocolic fistula was detected.PRESENTATION OF CASEShe presented with recurrent urinary tract infections and left flank pain. Investigations revealed a nonfunctioning left kidney with a large staghorn calculus and features suggestive of xanthogranulomatous pyelonephritis (XPG). At nephrectomy, an incidental renocolic fistula was found and excised.DISCUSSIONXGP is a rare, chronic inflammatory disorder of the kidney characterized by a destructive mass invading the renal parenchyma. Renocolic fistulae complicating XGP are uncommon and not widely reported in the literature.CONCLUSIONHerein, we describe a case of XGP with renocolic fistula formation, its management and a review of the literature

Entanglement of indistinguishable particles in condensed matter physics

The concept of entanglement in systems where the particles are indistinguishable has been the subject of much recent interest and controversy. In this paper we study the notion of entanglement of particles introduced by Wiseman and Vaccaro [Phys. Rev. Lett. 91, 097902 (2003)] in several specific physical systems, including some that occur in condensed matter physics. The entanglement of particles is relevant when the identical particles are itinerant and so not distinguished by their position as in spin models. We show that entanglement of particles can behave differently to other approaches that have been used previously, such as entanglement of modes (occupation-number entanglement) and the entanglement in the two-spin reduced density matrix. We argue that the entanglement of particles is what could actually be measured in most experimental scenarios and thus its physical significance is clear. This suggests entanglement of particles may be useful in connecting theoretical and experimental studies of entanglement in condensed matter systems.Comment: 13 pages, 6 figures, comments welcome, published version (minor changes, added references

Putting the "I" in Interaction: interactive interfaces personalized to the individual

Interactive data exploration and analysis is an inherently personal process. One's background, experience, interests, cognitive style, personality, and other sociotechnical factors often shape such a process, as well as the provenance of exploring, analyzing, and interpreting data. This viewpoint posits both what personal information and how such personal information could be taken into account to design more effective visual analytic systems, a valuable and under-explored direction