No abstract

Abstract. We review the differences in first order phase transition of single and multi-component systems, and then discuss the crystalline structure expected to exist in the mixed confined-deconfined phase of hadronic matter. The particular context of neutron stars is chosen for illustration. The qualitative results are general and apply for example to the vapor-liquid transition in subsaturated asymmetric nuclear matter.

We have theoretically investigated the tuning of Casimir forces by means of an external magnetic field. We have found that the Casimir force between two homogeneous slabs can be tuned by the external field in two ways. One is to add cap layers to the two dielectric slabs. The other is to insert a new dielectric layer into the cavity made of the two slabs. Since the dielectric constants of the materials used as the cap layers or the inserted layers depend on the external magnetic field, the Casimir force can be modified significantly by the external magnetic field. Our results show that it is possible to control the Casimir interaction in the fabrication of materials by an external field.

It is pointed out that the possibility of teleporting an arbitrary unknown one-particle spin state is crucially connected with the maximal entanglement of the Einstein-Podolsky-Rosen pair, whose one-particle reduced density matrix is (i)ϭ 1 2 I 2 (iϭ1,2). It is shown that, to teleport an arbitrary k-particle spin state, one must prepare an ancillary N-particle (Nу2k) entangled state, whose k-particle reduced density matrix has the form (1/2 k )I 2 k (I 2 k is the 2 k ϫ2 k identity matrix͒. An alternative approach to constructing many-particle entangled states is developed by using R x (), the collective rotation of around a given axis ͑say, x axis͒. The entangled states constructed by using R x () operating on the basis of angular momentum uncoupling representation are just the GHZ states, which cannot be used for the teleportation of an arbitrary k (у2) particle spin state. The entangled states constructed by using R x () operating on the basis of angular momentum coupling representation turn out to be effective for the teleportation of an arbitrary multiparticle state. A formal extension of the scheme of Bennett et al. to deal with the teleportation of an arbitrary two ͑or more͒ particle spin state is discussed.

Single-photon Michelson interferometry as a probe to macroscopic quantum mechanics is considered. With dual output readout at both the bright and dark ports, it is shown that a nonlocal, linear superposition of two Schrödinger cats may be generated by the opto-mechanical coupling of a single photon with a movable macroscopic quantum mirror in one arm of the interferometer. With a balanced homodyne readout scheme, a CHSH inequality may be formulated and the violation of which serves to verify the nonlocality of the two spacelike separated Schrödinger cats. The relevance of this result in our understanding of possible wave function collapse dynamics is briefly touched upon. Macroscopic entangled state of two mirrors generated by opto-mechanical coupling and the associated CHSH inequality are also discussed.