Optomechanics with molecules in a strongly pumped ring cavity

Cavity cooling of an atom works best on a cyclic optical transition in the strong coupling regime near resonance, where small cavity photon numbers suffice for trapping and cooling. Due to the absence of closed transitions a straightforward application to molecules fails: optical pumping can lead the particle into uncoupled states. An alternative operation in the far off-resonant regime generates only very slow cooling due to the reduced field-molecule coupling. We predict to overcome this by using a strongly driven ring-cavity operated in the sideband cooling regime. As in the optomechanical setups one takes advantage of a collectively enhanced field-molecule coupling strength using a large photon number. A linearized analytical treatment confirmed by full numerical quantum simulations predicts fast cooling despite the off-resonant small single molecule - single photon coupling. Even ground state cooling can be obtained by tuning the cavity field close to the Anti-stokes sideband for sufficiently high trapping frequency. Numerical simulations show quantum jumps of the molecules between the lowest two trapping levels, which can be be directly and continuously monitored via scattered light intensity detection

Hybrid stars in the light of the massive pulsar PSR J1614-2230

We perform a systematic study of hybrid star configurations using several parametrizations of a relativistic mean-field hadronic EoS and the NJL model for three-flavor quark matter. For the hadronic phase we use the stiff GM1 and TM1 parametrizations, as well as the very stiff NL3 model. In the NJL Lagrangian we include scalar, vector and 't Hooft interactions. The vector coupling constant $g_v$ is treated as a free parameter. We also consider that there is a split between the deconfinement and the chiral phase transitions which is controlled by changing the conventional value of the vacuum pressure $- \Omega_0$ in the NJL thermodynamic potential by $- (\Omega_0 + \delta \Omega_0)$, being $\delta \Omega_0$ a free parameter. We find that, as we increase the value of $\delta \Omega_0$, hybrid stars have a larger maximum mass but are less stable, i.e. hybrid configurations are stable within a smaller range of central densities. For large enough $\delta \Omega_0$, stable hybrid configurations are not possible at all. The effect of increasing the coupling constant $g_v$ is very similar. We show that stable hybrid configurations with a maximum mass larger than the observed mass of the pulsar PSR J1614-2230 are possible for a large region of the parameter space of $g_v$ and $\delta \Omega_0$ provided the hadronic equation of state contains nucleons only. When the baryon octet is included in the hadronic phase, only a very small region of the parameter space allows to explain the mass of PSR J1614-2230. We compare our results with previous calculations of hybrid stars within the NJL model. We show that it is possible to obtain stable hybrid configurations also in the case $\delta \Omega_0=0$ that corresponds to the conventional NJL model for which the pressure and density vanish at zero temperature and chemical potential.Comment: 7 pages, 5 figures; typos in Table 1 have been correcte

Course of neuromyelitis optica during inadvertent pregnancy in a patient treated with rituximab

In neuromyelitis optica (NMO), the monoclonal B-cell antibody rituximab is a therapeutic option. Little is known about the course of NMO and the safety of rituximab during pregnancy. In this study, we report the clinical course of a patient with NMO after application of rituximab 1 week before inadvertent conception. Mother and child did not experience any adverse event, and the postpartum development of the baby was completely normal up to 15 months. Clinical course of NMO was stable during the entire pregnancy. This case illustrates a favorable outcome in a pregnant NMO patient and her child after therapy with rituximab

Emittance growth in linear induction accelerators

The Dual-Axis Radiographic Hydrotest (DARHT) facility uses bremsstrahlung radiation source spots produced by the focused electron beams from two linear induction accelerators (LIAs) to radiograph large hydrodynamic experiments driven by high explosives. Radiographic resolution is determined by the size of the source spot, and beam emittance is the ultimate limitation to spot size. On the DARHT Axis-II LIA we measure an emittance higher than predicted by theoretical simulations, and even though this axis produces sub-millimeter source spots, we are exploring ways to improve the emittance. Some of the possible causes for the discrepancy have been investigated using particle-in-cell (PIC) codes, although most of these are discounted based on beam measurements. The most likely source of emittance growth is a mismatch of the beam to the magnetic transport, which can cause beam halo.Comment: 20th Int. Conf. on High-Power Particle Beams, Washington, DC, May, 201

Expansion of pinched hypersurfaces of the Euclidean and hyperbolic space by high powers of curvature

We prove convergence results for expanding curvature flows in the Euclidean and hyperbolic space. The flow speeds have the form $F^{-p}$, where $p>1$ and $F$ is a positive, strictly monotone and 1-homogeneous curvature function. In particular this class includes the mean curvature $F=H$. We prove that a certain initial pinching condition is preserved and the properly rescaled hypersurfaces converge smoothly to the unit sphere. We show that an example due to Andrews-McCoy-Zheng can be used to construct strictly convex initial hypersurfaces, for which the inverse mean curvature flow to the power $p>1$ loses convexity, justifying the necessity to impose a certain pinching condition on the initial hypersurface.Comment: 18 pages. We included an example for the loss of convexity and pinching. In the third version we dropped the concavity assumption on F. Comments are welcom

Temperature dependence of single-particle properties in nuclear matter

The single-nucleon potential in hot nuclear matter is investigated in the framework of the Brueckner theory by adopting the realistic Argonne V18 or Nijmegen 93 two-body nucleon-nucleon interaction supplemented by a microscopic three-body force. The rearrangement contribution to the single-particle potential induced by the ground state correlations is calculated in terms of the hole-line expansion of the mass operator and provides a significant repulsive contribution in the low-momentum region around and below the Fermi surface. Increasing temperature leads to a reduction of the effect, while increasing density makes it become stronger. The three-body force suppresses somewhat the ground state correlations due to its strong short-range repulsion, increasing with density. Inclusion of the three-body force contribution results in a quite different temperature dependence of the single-particle potential at high enough densities as compared to that adopting the pure two-body force. The effects of three-body force and ground state correlations on the nucleon effective mass are also discussed.Comment: 14 pages, 5 figure