PHASE BEHAVIOUR OF FIRST - ORDER SYSTEMS

Phenomenological modelling of first order phase transitions in magnetic systems

First Order Electroweak Phase

We consider the eeect of the presence of a hypermagnetic eld at the electroweak phase transition. Screening of the Z-component inside a bubble of the broken phase delays the phase transition and makes it stronger rst order. We show that the sphaleron constraint can be evaded for m H up to 100 GeV if a B Y > 0:3T 2 exists at the time of the EW phase transition , thus resurrecting the possibility...

First-Order Phase Transitions in Frustrated Spin Systems

We give a short review of our recent works on the first-order quantum phase transitions in frustrated spin chains with orthogonal-dimer structure. When the ratio of the competing antiferromagnetic exchange couplings is varied, a first-order transition occurs between the dimer phase and the plaquette phase, which is accompanied by the discontinuity in the spin excitation gap. We further show tha...

Phase Behaviour of Colloidal Systems

torting the helical structure of the phase) and the nematic phase develops when the equilibrium pitch of the cholesteric phase becomes larger than the sample thick­ ness. This transition is first order and can easily be observed when approaching a smectic phase, because the cholesteric pitch diverges at this transition. In this way, it is possible to observe the growth of the cholesteric phase ...

Quantum first order phase transitions

The scaling theory of critical phenomena has been successfully extended for classical first order transitions even though the correlation length does not diverge in these transitions. In this paper we apply the scaling ideas to quantum first order transitions. The usefulness of this approach is illustrated treating the problems of a superconductor coupled to a gauge field and of a biquadratic H...