A general method for computing kinetic isotope effects is described. The method uses the quantum-instanton approximation and is based on the thermodynamic integration with respect to the mass of the isotopes and on the path-integral Monte-Carlo evaluation of relevant thermodynamic quantities. The central ingredients of the method are the Monte-Carlo estimators for the logarithmic derivatives of...

We apply the de Broglie-Bohm interpretation to the Wheeler-DeWitt equation for the quantum FRW cosmological model with a minimal massless scalar field. We find that the quantum FRW cosmological model has quantum potential dominated solutions that avoid the initial and the final cosmological singularities. It is suggested that the quantum potential and the back-reaction of geometry and matter fi...

We give a general expression for the static potential energy of the gravitational interaction of two massive particles, in terms of an invariant vacuum expectation value of the quantized gravitational field. This formula holds for functional integral formulations of euclidean quantum gravity, regularized to avoid conformal instability. It could be regarded as the analogue of the Wilson loop of ...

Advances in nanotechnology have led to the development of novel fluorescent probes called quantum dots. Quantum dots have revolutionalized the processes of tagging molecules within research settings and are improving sentinel lymph node mapping and identification in vivo studies. As the unique physical and chemical properties of these fluorescent probes are being unraveled, new potential method...

The PSP model [1], a generalized Surface-Potential (SP) model, has been chosen to be an industry standard for the next generation, 60nm, technology. In order to include quantum effects within surface potential models we use asymptotic analysis techniques [2], [3] applied to the the Density-Gradient equations [4]. Our quantum modified surface potential (SP) results from the ability to obtain a f...

In this paper, we have investigated the dependence of the spectral entanglement and indistinguishability of photon pairs produced by the spontaneous parametric down-conversion (SPDC) procedure on the bandwidth of spectral filters used in the detection setup. The SPDC is a three-wave mixing process which occurs in a nonlinear crystal and generates entangled photon pairs and utilizes as one of th...

the time evaluation of quantum entropy in a four-level double- type atomic system is theoretically investigated. quantum entanglement of the atom and its spontaneous emission fields is then discussed via quantum entropy. it is found that the degree of entanglement can be increased by the quantum interference induced by spontaneous emission. the phase dependence of the atom-field entanglement is...