Atomic quantum superposition state generation via optical probing

We analyze the performance of a protocol to prepare an atomic ensemble in a superposition of two macroscopically distinguishable states. The protocol relies on conditional measurements performed on a light field, which interacts with the atoms inside an optical cavity prior to detection, and we investigate cavity enhanced probing with continuous beams of both coherent and squeezed light. The stochastic master equations used in the analysis are expressed in terms of the Hamiltonian of the probed system and the interaction between the probed system and the probe field and are thus quite generally applicable.Comment: 10 pages, 9 figure

Unitary representations of nilpotent super Lie groups

We show that irreducible unitary representations of nilpotent super Lie groups can be obtained by induction from a distinguished class of sub super Lie groups. These sub super Lie groups are natural analogues of polarizing subgroups that appear in classical Kirillov theory. We obtain a concrete geometric parametrization of irreducible unitary representations by nonnegative definite coadjoint orbits. As an application, we prove an analytic generalization of the Stone-von Neumann theorem for Heisenberg-Clifford super Lie groups

Reduction in DNA binding activity of the transcription factor Pax-5a in B lymphocytes of aged mice

Aging has been associated with intrinsic changes of the humoral immune response, which may lead to an increased occurrence of autoimmune disorders and pathogenic susceptibility. The transcription factor Pax-5 is a key regulator of B cell development. Pax-5a/B cell-specific activator protein and an alternatively spliced isoform, Pax-Sd, may have opposing functions in transcriptional regulation due to the lack of a transactivation domain in Pax-Sd. To study B cell-specific changes that occur during the aging process, we investigated expression patterns of Pax-Sa and Sd in mature B cells of young and aged mice. RNase protection assays showed a similar transcriptional pattern for both age groups that indicates that aging has no affect on transcription initiation or alternative splicing for either isoform, In contrast, a significant reduction in the DNA binding activity of Pax-Sa but not Pax-Sd protein was observed in aged B cells in vitro, while Western blot analyses showed that similar levels of Pax-Sa and Sd proteins were present in both age groups. The observed decrease in Pax-Sa binding activity correlated with changes in expression of two Pax-5 target genes in aged B cells, Expression of the Ig J chain and the secreted form of Ig mu, which are both known to be suppressed by Pax-Sa in mature B cells, were increased in B cells of aged mice, Together, our studies suggest that changes associated with the aging phenotype cause posttranslational modification(s) of Pax-Sa but not Pax-Sd, which may lead to an abnormal B cell phenotype in aged mice, associated with elevated levels of J chain, and secretion of IgM

Hilar Mossy Cells Provide the First Glutamatergic Synapses to Adult-Born Dentate Granule Cells

Adult-generated granule cells (GCs) in the dentate gyrus must establish synapses with preexisting neurons to participate in network activity. To determine the source of early glutamatergic synapses on newborn GCs in adult mice, we examined synaptic currents at the developmental stage when NMDA receptor-mediated silent synapses are first established. We show that hilar mossy cells provide initial glutamatergic synapses as well as disynaptic GABAergic input to adult-generated dentate GCs

Infinite qubit rings with maximal nearest neighbor entanglement: the Bethe ansatz solution

We search for translationally invariant states of qubits on a ring that maximize the nearest neighbor entanglement. This problem was initially studied by O'Connor and Wootters [Phys. Rev. A {\bf 63}, 052302 (2001)]. We first map the problem to the search for the ground state of a spin 1/2 Heisenberg XXZ model. Using the exact Bethe ansatz solution in the limit of an infinite ring, we prove the correctness of the assumption of O'Connor and Wootters that the state of maximal entanglement does not have any pair of neighboring spins ``down'' (or, alternatively spins ``up''). For sufficiently small fixed magnetization, however, the assumption does not hold: we identify the region of magnetizations for which the states that maximize the nearest neighbor entanglement necessarily contain pairs of neighboring spins ``down''.Comment: 10 pages, 4 figures; Eq. (45) and Fig. 3 corrected, no qualitative change in conclusion