• atoms
  • In quantum optics, a superradiant phase transition is a phase transition that occurs in a collection of fluorescent emitters (such as atoms), between a state containing few electromagnetic excitations (as in the electromagnetic vacuum) and a superradiant state with many electromagnetic excitations trapped inside the emitters. (wikipedia.org)
  • The superradiant phase transition was originally predicted by the Dicke model of superradiance, which assumes that atoms have only two energetic levels and that these interact with only one mode of the electromagnetic field. (wikipedia.org)
  • The phase transition occurs when the strength of the interaction between the atoms and the field is greater than the energy of the non-interacting part of the system. (wikipedia.org)
  • However, both the original derivation and the later corrections leading to nonexistence of the transition - due to Thomas-Reiche-Kuhn sum rule canceling for the harmonic oscillator the needed inequality to impossible negativity of the interaction - were based on the assumption that the quantum field operators are commuting numbers, and the atoms do not interact with the static Coulomb forces. (wikipedia.org)
  • behavior
  • Although absolute zero is not physically realizable, characteristics of the transition can be detected in the system's low-temperature behavior near the critical point. (wikipedia.org)
  • This quantum critical behavior manifests itself in unconventional and unexpected physical behavior like novel non Fermi liquid phases. (wikipedia.org)
  • A superradiant phase transition is formally predicted by the critical behavior of the resonant Jaynes-Cummings model, describing the interaction of only one atom with one mode of the electromagnetic field. (wikipedia.org)
  • Condensed matter physicists seek to understand the behavior of these phases by using physical laws. (wikipedia.org)
  • Shortly after, in 1869, Irish chemist Thomas Andrews studied the phase transition from a liquid to a gas and coined the term critical point to describe the condition where a gas and a liquid were indistinguishable as phases, and Dutch physicist Johannes van der Waals supplied the theoretical framework which allowed the prediction of critical behavior based on measurements at much higher temperatures. (wikipedia.org)
  • solids
  • The transition between different molecular structures (polymorphs, allotropes or polyamorphs), especially of solids, such as between an amorphous structure and a crystal structure, between two different crystal structures, or between two amorphous structures. (wikipedia.org)
  • Phase equilibrium has been considered within the context of their physical similarities, with appropriate scaling, to elastic solids. (wikipedia.org)
  • equilibrium
  • When water vapor condenses (an equilibrium fractionation), the heavier water isotopes (18O and 2H) become enriched in the liquid phase while the lighter isotopes (16O and 1H) tend toward the vapor phase. (wikipedia.org)
  • transformations
  • Transformations connecting one Kuryshkin's algebras class to another are degenerated so that the transition from one class of equivalency to another is similar to a phase transition. (springer.com)
  • The martensitic transformation which occurs as one of the many phase transformations in carbon steel and stands as a model for displacive phase transformations. (wikipedia.org)
  • He is also credited with wider studies in synthesis of nanocomposites, phase transformations, large superheating phenomenon during melting, dissimilar joining processes, surface modifications and nanostructured magnetic alloys. (wikipedia.org)
  • symmetry
  • Usually we think of phase transitions in terms of symmetry breaking (Landau Ginzburg). (physicsforums.com)
  • You can go from one phase to another without breaking symmetry. (physicsforums.com)
  • In a superfluid phase, this symmetry is spontaneously broken. (wikipedia.org)
  • The superfluid is characterized by long-range phase coherence, a spontaneous breaking of the Hamiltonian's continuous U ( 1 ) {\displaystyle U(1)} symmetry, a non-zero compressibility and superfluid susceptibility. (wikipedia.org)
  • At non-zero temperature, in certain parameter regimes there will also be a regular fluid phase which does not break the U ( 1 ) {\displaystyle U(1)} symmetry and does not display phase coherence. (wikipedia.org)
  • exhibit
  • These phases of matter exhibit properties and symmetries which can potentially be exploited for technological purposes and the benefit of mankind. (wikipedia.org)
  • displaystyle
  • A phase transition from water to ice, for example, involves latent heat (a discontinuity of the internal energy U {\displaystyle U} ) and is of first order. (wikipedia.org)
  • At zero temperature, the Bose-Hubbard model (in the absence of disorder) is in either a Mott insulating state at small t / U {\displaystyle t/U} , or in a superfluid state at large t / U {\displaystyle t/U} . The Mott insulating phases are characterized by integer boson densities, by the existence of an energy gap for particle-hole excitations, and by zero compressibility. (wikipedia.org)
  • superfluid
  • The superfluid transition in liquid helium is an example of this. (wikipedia.org)
  • The model rose to prominence in the 1980s after it was found to capture the essence of the superfluid-insulator transition in a way that was much more mathematically tractable than fermionic metal-insulator models. (wikipedia.org)
  • The Bose glass is a Griffiths phase, and can be thought of as a Mott insulator containing rare 'puddles' of superfluid. (wikipedia.org)
  • The Bose glass phase is characterized by a finite compressibility, the absence of a gap, and by an infinite superfluid susceptibility. (wikipedia.org)
  • undergo
  • If the interaction with the field is so strong that the system collapses in the harmonic approximation and complex polariton frequencies (soft modes) appear, then the physical system with nonlinear terms of the higher order becomes the system with the Mexican hat-like potential, and will undergo ferroelectric-like phase transition. (wikipedia.org)
  • While there are physically higher terms in the true system, the system in this regime will therefore undergo the phase transition. (wikipedia.org)
  • driven
  • The resulting effect may be viewed as a unique type of quantum phase transition that is driven by the size of the system rather than by an external field or coupling strength. (pnas.org)
  • processes
  • Processes of heat and mass transfer with phase transitions assume an important place in such modern technologies as thermal treatment and drying of materials, welding, metallurgy, heat protection, vacuum techniques, laser and electron-beam treatment of materials, and many other areas. (begellhouse.com)
  • exotic
  • This topic also remains controversial, and even if there is a curved structure present in the fusion process, there is debate in the literature over whether it is a cubic, hexagonal or more exotic extended phase. (wikipedia.org)
  • stable
  • In particular, we discuss the following aspects: a cascade of freezing transitions for confined colloids, stable one-component quasicrystals for charged colloids, reentrant melting and anisotropic solid phases for star polymer solutions and reentrant nematic ordering for suspensions of the tobacco-mosaic virus. (ebscohost.com)
  • readily
  • The transition can be readily understood by the use of the Holstein-Primakoff transformation applied to a two-level atom. (wikipedia.org)
  • Since PE has a small headgroup and readily forms inverted micelle phases it should, according to the stalk model, promote the formation of these stalks. (wikipedia.org)
  • model
  • We give a complete characterisation of the phase diagram of the model, and derive several criteria of the transient and recurrent regimes for the underlying stochastic process. (dur.ac.uk)
  • Where the linearized Poissonâ€"Boltzmann cell model fails: Spurious phase separation in charged colloidal suspensions. (ebscohost.com)
  • Specifically, there is a detectability transition in the stochastic block model, below which no algorithm can label nodes better than chance. (princeton.edu)