Entanglement entropy of dispersive media from thermodynamic entropy in one higher dimension

A dispersive medium becomes entangled with zero-point fluctuations in the vacuum. We consider an arbitrary array of material bodies weakly interacting with a quantum field and compute the quantum mutual information between them. It is shown that the mutual information in D dimensions can be mapped to classical thermodynamic entropy in D+1 dimensions. As a specific example, we compute the mutual information both analytically and numerically for a range of separation distances between two bodies in D=2 dimensions and find a logarithmic correction to the area law at short separations. A key advantage of our method is that it allows the strong subadditivity property---notoriously difficult to prove for quantum systems---to be easily verified.Comment: Corrected typos. Added reference

General calculation of 4f−5d4f-5d transition rates for rare-earth ions using many-body perturbation theory

The $4f-5d$ transition rates for rare-earth ions in crystals can be calculated with an effective transition operator acting between model $4f^N$ and $4f^{N-1}5d$ states calculated with effective Hamiltonian, such as semi-empirical crystal Hamiltonian. The difference of the effective transition operator from the original transition operator is the corrections due to mixing in transition initial and final states of excited configurations from both the center ion and the ligand ions. These corrections are calculated using many-body perturbation theory. For free ions, there are important one-body and two-body corrections. The one-body correction is proportional to the original electric dipole operator with magnitude of approximately 40% of the uncorrected electric dipole moment. Its effect is equivalent to scaling down the radial integral \ME {5d} r {4f}, to about 60% of the uncorrected HF value. The two-body correction has magnitude of approximately 25% relative to the uncorrected electric dipole moment. For ions in crystals, there is an additional one-body correction due to ligand polarization, whose magnitude is shown to be about 10% of the uncorrected electric dipole moment.Comment: 10 pages, 1 figur

Oxygen complexes formed at 4 K

Storage stability of oxygen complexes at 4

Modulation of HU-DNA interactions by salt concentration and applied force.

HU is one of the most abundant proteins in bacterial chromosomes and participates in nucleoid compaction and gene regulation. We report experiments using DNA stretching that study the dependence of DNA condensation by HU on force, salt and HU concentration. Previous experiments at sub-physiological salt levels revealed that low concentrations of HU could compact DNA, whereas larger HU concentrations formed a DNA-stiffening complex. Here we report that this bimodal binding behavior depends sensitively on salt concentration. Only the compaction mode was observed for 150 mM and higher NaCl levels, i.e. for physiological salt concentrations. Similar results were obtained for the more physiological salt K-glutamate. Real-time studies of dissociation kinetics revealed that HU unbound slowly (minutes to hours under the conditions studied) but completely for salt concentrations at or above 100 mM NaCl; the lifetime of HU complexes was observed to increase with the HU concentration at which the complexes were formed, and to decrease with salt concentration. Higher salt levels of 300 mM NaCl completely eliminated observable HU binding to DNA. Finally, we observed that the dissociation kinetics depend on force applied to the DNA: increased applied force in the sub-piconewton range accelerates dissociation, suggesting a mechanism for DNA tension to regulate chromosome structure and gene expression

Factors affecting the open-circuit voltage and electrode kinetics of some iron/titanium redox flow cells

Performance of the iron-titanium redox flow cell was studied as a function of acid concentration. Anion permeable membranes separated the compartments. Electrodes were graphite cloth. Current densities ranged up to 25 mA/square centimeter. Open-circuit and load voltages decreased as the acidity was increased on the iron side as predicted. On the titanium side, open-circuit voltages decreased as the acidity was increased in agreement with theory, but load voltages increased due to decreased polarization with increasing acidity. High acidity on the titanium side coupled with low acidity on the iron side gives the best load voltage, but such cells show voltage losses as they are repeatedly cycled. Analyses show that the bulk of the voltage losses are due to diffusion of acid through the membrane

Induction motor control system with voltage controlled oscillator circuit

A voltage controlled oscillator circuit is reported in which there are employed first and second differential amplifiers. The first differential amplifier, being employed as an integrator, develops equal and opposite slopes proportional to an input voltage, and the second differential amplifier functions as a comparator to detect equal amplitude positive and negative selected limits and provides switching signals which gate a transistor switch. The integrating differential amplifier is switched between charging and discharging modes to provide an output of the first differential amplifier which upon the application of wave shaping provides a substantially sinusoidal output signal. A two phased version with a second integrator provides a second 90 deg phase shifted output for induction motor control

Zirconium carbide as an electrocatalyst for the chromous-chromic redox couple

Zirconium carbide is used as a catalyst in a REDOX cell for the oxidation of chromous ions to chromic ions and for the reduction of chromic ions to chromous ions. The zirconium carbide is coated on an inert electronically conductive electrode which is present in the anode fluid of the cell