The authors demonstrate an optical buffer architecture which is implemented using quantum dot semiconductor optical amplifiers (QD-SOAs) in order to achieve wavelength conversion with regenerative capabilities, for all optical packet switched networks. The architecture consists of cascaded programmable delay stages that minimise the number of wavelength converters required to implement the buff...

Motivated by the recently demonstrated ability to attach quantum dots to polymers at well-defined locations, we propose a condensed-phase analog of the ion-trap quantum computer: a scheme for quantum computation using chemically assembled semiconductor nanocrystals attached to a linear support. The linear support is either a molecular string ~e.g., DNA! or a nanoscale rod. The phonon modes of t...

In this work, we discuss the scattering theory of local, relativistic quantum fields with indefinite metric. Since the results of Haag–Ruelle theory do not carry over to the case of indefinite metric [4], we propose an axiomatic framework for the construction of inand outstates, such that the LSZ asymptotic condition can be derived from the assumptions. The central mathematical object for this ...

Motivated by recent works on “Higgsless theories,” I discuss an SU(2)0 × SU(2) × U(1) gauge theory with arbitrary bifundamental (or custodial SU(2) preserving) symmetry breaking between the gauge subgroups and with ordinary matter transforming only under the U(1) and SU(2)0. When the couplings, gj, of the other SU(2)s are very large, this reproduces the standard model at the tree level. I calcu...

We discuss the classical mechanics on the Grassmannian and the Disc modeled on the ideal L (2,∞). We apply methods of geometric quantization to these systems. Their relation to a flat symplectic space is also discussed. 1 Introduction We will analyze geometric quantization of a classical system which has as its phase space the infinite dimensional Grassmannian or the Disc modeled on the ideal L...

Motivated by recent works on “Higgsless theories,” I discuss an SU(2)0 × SU(2) × U(1) gauge theory with arbitrary bifundamental (or custodial SU(2) preserving) symmetry breaking between the gauge subgroups and with ordinary matter transforming only under the U(1) and SU(2)0. When the couplings, gj, of the other SU(2)s are very large, this reproduces the standard model at the tree level. I calcu...

We provide exact analytical expressions for the magnetic susceptibility function in the high temperature expansion for finite Heisenberg spin systems with an arbitrary coupling matrix, arbitrary single-spin quantum number, and arbitrary number of spins. The results can be used to determine unknown exchange parameters from zero-field magnetic susceptibility measurements without diagonalizing the...

Motivated by recent works on “Higgsless theories,” I discuss an SU(2)0 × SU(2) × U(1) gauge theory with arbitrary bifundamental (or custodial SU(2) preserving) symmetry breaking between the gauge subgroups and with ordinary matter transforming only under the U(1) and SU(2)0. When the couplings, gj, of the other SU(2)s are very large, this reproduces the standard model at the tree level. I calcu...

A cluster model for active site of nanotube (C48) was presented and investigated the geometricstructure and thermochemical parameters. Quantum-mechanical calculations were performed at theHF / 510-30, 6-310, 6-3 IG• and 6-310" levels of theory in the gas phase and three solvents atfour temperatures. Also, nuclear shielding parameters of the active site of nanotube have been takeninto account us...

We propose a technique for performing quantum state tomography of photonic polarization-encoded multiqubit states. Our method uses a single rotating wave plate, a polarizing beam splitter, and two photon-counting detectors per photon mode. As the wave plate rotates, the photon counters measure a pseudocontinuous signal which is then Fourier transformed. The density matrix of the state is recons...