We explore sufficient conditions for inseparability in mixed states with a globally conserved charge, such as particle number. argue that even separable may contain entanglement fixed charge sectors, long the state cannot be separated into charge-conserving components. As witness of symmetric we study number (NE), $\mathrm{\ensuremath{\Delta}}{S}_{m}$, defined entropy change due to subsystem's ...

We address the pair of conjugated field modes obtained from parametricdownconversion as a convenient system to analyze the quantum-classical transition in the continuous variable regime. We explicitly evaluate intensity correlations, negativity and entanglement for the system in a thermal state and show that a hierarchy of nonclassicality thresholds naturally emerges in terms of thermal and dow...

We hypothesize that there is a general bias, based on both innate predispositions and experience, in animals and humans, to give greater weight to negative entities (e.g., events, objects, personal traits). This is manifested in 4 ways: (a) negative potency (negative entities are stronger than the equivalent positive entities), (b) steeper negative gradients (the negativity of negative events g...

The radiation pressure of two laser beams detuned from resonance in an optical cavity can create a stable optical trap for a mechanical oscillation mode of a movable cavity mirror. Here it is shown that such a configuration entangles the output light fields via interaction with a mirror that is suspended as a pendulum. The degree of entanglement is quantified spectrally using the logarithmic ne...

The entanglement in a general mixed spin chain with arbitrary spin S and 1/2 is investigated in the thermodynamical limit. The entanglement is witnessed by the magnetic susceptibility which decides a characteristic temperature for an entangled thermal state. The characteristic temperature is nearly proportional to the interaction J and the mixed spin S. The bound of negativity is obtained on th...

Using the normally ordered Gaussian form of displaced-squeezed thermal field characteristic of average photon number n̄, we introduce the photon-added squeezed thermo state (PASTS) and investigate its statistical properties, such as Mandel’s Q-parameter, number distribution (as a Legendre polynomial), the Wigner function. We then study its decoherence in a photon-loss channel in term of the nega...

We investigate the entanglement dynamics between two dipole-coupled qubits interacting with vacuum or thermal fields of lossless resonators. Double Jaynes-Cummings model and two-atom Jaynes-Cummings model are considered taking into account detuning and direct dipole-dipole interaction. Using the dressed-states technique we derive the exact solutions for models under consideration. The computer ...