Nonlinear dynamics of a cigar-shaped Bose-Einstein condensate coupled with a single cavity mode

We investigate the nonlinear dynamics of a combined system which is composed of a cigar-shaped Bose-Einstein condensate and an optical cavity. The two sides couple dispersively. This system is characterized by its nonlinearity: after integrating out the freedom of the cavity mode, the potential felt by the condensate depends on the condensate itself. We develop a discrete-mode approximation for the condensate. Based on this approximation, we map out the steady configurations of the system. It is found that due to the nonlinearity of the system, the nonlinear levels of the system can fold up in some parameter regimes. That will lead to the breakdown of adiabaticity. Analysis of the dynamical stability of the steady states indicates that the same level structure also results in optical bistability.Comment: 8 pages, 5 figure

Vector magnetic field sensing by single nitrogen vacancy center in diamond

In this Letter, we proposed and experimentally demonstrated a method to detect vector magnetic field with a single nitrogen vacancy (NV) center in diamond. The magnetic field in parallel with the axis of the NV center can be obtained by detecting the electron Zeeman shift, while the Larmor precession of an ancillary nuclear spin close to the NV center can be used to measure the field perpendicular to the axis. Experimentally, both the Zeeman shift and Larmor precession can be measured through the fluorescence from the NV center. By applying additional calibrated magnetic fields, complete information of the vector magnetic field can be achieved with such a method. This vector magnetic field detection method is insensitive to temperature fluctuation and it can be applied to nanoscale magnetic measurement.Comment: 5 pages, 5 figure

Analytical model of non-Markovian decoherence in donor-based charge quantum bits

We develop an analytical model for describing the dynamics of a donor-based charge quantum bit (qubit). As a result, the quantum decoherence of the qubit is analytically obtained and shown to reveal non-Markovian features: The decoherence rate varies with time and even attains negative values, generating a non-exponential decay of the electronic coherence and a later recoherence. The resulting coherence time is inversely proportional to the temperature, thus leading to low decoherence below a material dependent characteristic temperature.Comment: 19 pages, 3 figure

Site Selective Antibody-Oligonucleotide Conjugation via Microbial Transglutaminase.

Nucleic Acid Therapeutics (NATs), including siRNAs and AntiSense Oligonucleotides (ASOs), have great potential to drug the undruggable genome. Targeting siRNAs and ASOs to specific cell types of interest has driven dramatic improvement in efficacy and reduction in toxicity. Indeed, conjugation of tris-GalNAc to siRNAs and ASOs has shown clinical efficacy in targeting diseases driven by liver hepatocytes. However, targeting non-hepatic diseases with oligonucleotide therapeutics has remained problematic for several reasons, including targeting specific cell types and endosomal escape. Monoclonal antibody (mAb) targeting of siRNAs and ASOs has the potential to deliver these drugs to a variety of specific cell and tissue types. However, most conjugation strategies rely on random chemical conjugation through lysine or cysteine residues resulting in conjugate heterogeneity and a distribution of Drug:Antibody Ratios (DAR). To produce homogeneous DAR-2 conjugates with two siRNAs per mAb, we developed a novel two-step conjugation procedure involving microbial transglutaminase (MTGase) tagging of the antibody C-terminus with an azide-functionalized linker peptide that can be subsequently conjugated to dibenzylcyclooctyne (DBCO) bearing oligonucleotides through azide-alkyne cycloaddition. Antibody-siRNA (and ASO) conjugates (ARCs) produced using this strategy are soluble, chemically defined targeted oligonucleotide therapeutics that have the potential to greatly increase the number of targetable cell types

Controlling suction by vapour equilibrium technique at different temperatures, application to the determination of the water retention properties of MX80 clay

Problems related to unsaturated soils are frequently encountered in geotechnical or environmental engineering works. In most cases, for the purpose of simplicity, the problems are studied by considering the suction effects on volume change or shear strength under isothermal conditions. Under isothermal condition, very often, a temperature independent water retention curve is considered in the analysis, which is obviously a simplification. When the temperature changes are too significant to be neglected, it is necessary to account for the thermal effects. In this paper, a method for controlling suction using the vapour equilibrium technique at different temperatures is presented. First, calibration of various saturated saline solutions was carried out from temperature of 20 degrees C to 60 degrees C. A mirror psychrometer was used for the measurement of relative humidity generated by saturated saline solutions at different temperatures. The results obtained are in good agreement with the data from the literature. This information was then used to determine the water retention properties of MX80 clay, which showed that the retention curve is shifting down with increasing of temperature

Quantum Phase Diffusion in a Small Underdamped Josephson Junction

Quantum phase diffusion in a small underdamped Nb/AlO$_x$/Nb junction ($\sim$ 0.4 $\mu$m$^2$) is demonstrated in a wide temperature range of 25-140 mK where macroscopic quantum tunneling (MQT) is the dominant escape mechanism. We propose a two-step transition model to describe the switching process in which the escape rate out of the potential well and the transition rate from phase diffusion to the running state are considered. The transition rate extracted from the experimental switching current distribution follows the predicted Arrhenius law in the thermal regime but is greatly enhanced when MQT becomes dominant.Comment: 4 pages, 4 figures, 1 tabl

Variable O VI and N V emission from the X-ray binary LMC X-3 : heating of the black hole companion

Based on high-resolution ultraviolet spectroscopy obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Cosmic Origins Spectrograph, we present new detections of Ovi and Nv emission from the black hole X-ray binary (XRB) system LMCX-3. We also update the ephemeris of the XRB using recent radial velocity measurements obtained with the echelle spectrograph on the Magellan-Clay telescope. We observe significant velocity variability of the UV emission, and we find that the Ovi and Nv emission velocities follow the optical velocity curve of the XRB. Moreover, the Ovi and Nv intensities regularly decrease between binary phase=0.5 and 1.0, which suggests that the source of the UV emission is increasingly occulted as the B star in the XRB moves from superior to inferior conjunction. These trends suggest that illumination of the B star atmosphere by the intense X-ray emission from the accreting black hole creates a hot spot on one side of the B star, and this hot spot is the origin of the Ovi and Nv emission. However, the velocity semiamplitude of the ultraviolet emission, K-UV approximate to 180 km s(-1), is lower than the optical semiamplitude; this difference could be due to rotation of the B star. Comparison of the FUSE observations taken in 2001 November and 2004 April shows a significant change in the Ovi emission characteristics: in the 2001 data, the Ovi region shows both broad and narrow emission features, while in 2004 only the narrow Ovi emission is clearly present. Rossi X-ray Timing Explorer data show that the XRB was in a high/soft state in the 2001 November epoch but was in a transitional state in 2004 April, so the shape of the X-ray spectrum might change the properties of the region illuminated on the B star and thus change the broad versus narrow characteristics of the UV emission. If our hypothesis about the origin of the highly ionized emission is correct, then careful analysis of the emission occultation could, in principle, constrain the inclination of the XRB and the mass of the black hole

Necrotic tumor growth: an analytic approach

The present paper deals with a free boundary problem modeling the growth process of necrotic multi-layer tumors. We prove the existence of flat stationary solutions and determine the linearization of our model at such an equilibrium. Finally, we compute the solutions of the stationary linearized problem and comment on bifurcation.Comment: 14 pages, 3 figure