Low-Energy Theorems for Gluodynamics at Finite Temperature

We generalize the low-energy theorems of gluodynamics to finite temperature. Examples of the theorems in the low and high temperature limits are given.Comment: 8 pages latex plus 1 postscript figur

Non-zero entropy density in the XY chain out of equilibrium

The von Neumann entropy density of a block of n spins is proved to be non-zero for large n in the non-equilibrium steady state of the XY chain constructed by coupling a finite cutout of the chain to the two infinite parts to its left and right which act as thermal reservoirs at different temperatures. Moreover, the non-equilibrium density is shown to be strictly greater than the density in thermal equilibrium

Nucleation versus Spinodal decomposition in a first order quark hadron phase transition

We investigate the scenario of homogeneous nucleation for a first order quark-hadron phase transition in a rapidly expanding background of quark gluon plasma. Using an improved preexponential factor for homogeneous nucleation rate, we solve a set of coupled equations to study the hadronization and the hydrodynamical evolution of the matter. It is found that significant supercooling is possible before hadronization begins. This study also suggests that spinodal decomposition competes with nucleation and may provide an alternative mechanism for phase conversion particularly if the transition is strong enough and the medium is nonviscous. For weak enough transition, the phase conversion may still proceed via homogeneous nucleation.Comment: LaTeX, 10 pages with 7 Postscript figures, more discussions and referencese added, typos correcte

Chiral Effective Lagrangian in the large-Nc limit: the nonet case

A U_L(3) \otimes U_R(3) low-energy effective lagrangian for the nonet of pseudogoldstone bosons that appear in the large-Nc limit of QCD is presented including terms up to four derivatives and explicit symmetry breaking terms up to quadratic in the quark masses. The one-loop renormalization of the couplings is worked out using the heat-kernel technique and dimensional renormalization. The calculation is carried through for U_L(n_l) \otimes U_R(n_l), thus allowing for a generic number n_l of light quark flavours. The crucial advantages that the expansion in powers of 1/N_c bring about are discussed. Special emphasis is put in pointing out what features are at variance with the SU_L \otimes SU_R results when the singlet \eta' is included in the theory.Comment: 41 pages, Late

Tensor network states and geometry

Tensor network states are used to approximate ground states of local Hamiltonians on a lattice in D spatial dimensions. Different types of tensor network states can be seen to generate different geometries. Matrix product states (MPS) in D=1 dimensions, as well as projected entangled pair states (PEPS) in D>1 dimensions, reproduce the D-dimensional physical geometry of the lattice model; in contrast, the multi-scale entanglement renormalization ansatz (MERA) generates a (D+1)-dimensional holographic geometry. Here we focus on homogeneous tensor networks, where all the tensors in the network are copies of the same tensor, and argue that certain structural properties of the resulting many-body states are preconditioned by the geometry of the tensor network and are therefore largely independent of the choice of variational parameters. Indeed, the asymptotic decay of correlations in homogeneous MPS and MERA for D=1 systems is seen to be determined by the structure of geodesics in the physical and holographic geometries, respectively; whereas the asymptotic scaling of entanglement entropy is seen to always obey a simple boundary law -- that is, again in the relevant geometry. This geometrical interpretation offers a simple and unifying framework to understand the structural properties of, and helps clarify the relation between, different tensor network states. In addition, it has recently motivated the branching MERA, a generalization of the MERA capable of reproducing violations of the entropic boundary law in D>1 dimensions.Comment: 18 pages, 18 figure

Isolated housewives and complex maternal worlds: the significance of social contacts between women with young children in industrial societies.

This article reconsiders the picture of the mother of young children in industrialised societies as the 'isolated housewife', suggesting this notion is by no means straightforward. We suggest there is considerable evidence for the existence of mothers' social contacts and their significance both as 'work' and 'friendship' in industrial societies. A pre-occupation with the notion of the 'isolation' of 'housewives' has led social researchers to neglect sustained examination of the social relationships within which many/most mothers are involved on a day-to-day basis. Complexities of interpretation, for example what 'isolation' can actually mean, need to be drawn out from the existing literature. Evidence presented from two recent ethnographic studies shows patterned opportunities/constraints occurring in relation to mothers' social contacts within localised settings, whether through organised groups or other personal ties. The complex nature of individual women's social contacts is thus brought out. Some key questions are raised for the importance to sociology, anthropology and social policy of these apparently insignificant or invisible women's networks