In condensed matter physics, a Bose–Einstein condensate (BEC) is a state of matter that is typically formed when a gas of bosons at very low densities is cooled to temperatures very close to absolute zero. Under such conditions, a large fraction of bosons occupy the lowest quantum state, at which microscopic quantum mechanical phenomena, particularly wavefunction interference, become apparent macroscopically. More generally, condensation refers to the appearance of macroscopic occupation of one or several states: for example, in BCS theory, a superconductor is a condensate of Cooper pairs. As such, condensation can be associated with phase transition, and the macroscopic occupation of the state is the order parameter.
In physics, polaritons are quasiparticles resulting from strong coupling of electromagnetic waves with an electric or magnetic dipole-carrying excitation. They are an expression of the common quantum phenomenon known as level repulsion, also known as the avoided crossing principle. Polaritons describe the crossing of the dispersion of light with any interacting resonance. To this extent polaritons can also be thought of as the new normal modes of a given material or structure arising from the strong coupling of the bare modes, which are the photon and the dipolar oscillation. The polariton is a bosonic quasiparticle, and should not be confused with the polaron, which is an electron plus an attached phonon cloud.
Electromagnetically induced transparency (EIT) is a coherent optical nonlinearity which renders a medium transparent within a narrow spectral range around an absorption line. Extreme dispersion is also created within this transparency "window" which leads to "slow light", described below. It is in essence a quantum interference effect that permits the propagation of light through an otherwise opaque atomic medium.
In physics, a quantum vortex represents a quantized flux circulation of some physical quantity. In most cases, quantum vortices are a type of topological defect exhibited in superfluids and superconductors. The existence of quantum vortices was first predicted by Lars Onsager in 1949 in connection with superfluid helium. Onsager reasoned that quantisation of vorticity is a direct consequence of the existence of a superfluid order parameter as a spatially continuous wavefunction. Onsager also pointed out that quantum vortices describe the circulation of superfluid and conjectured that their excitations are responsible for superfluid phase transitions. These ideas of Onsager were further developed by Richard Feynman in 1955 and in 1957 were applied to describe the magnetic phase diagram of type-II superconductors by Alexei Alexeyevich Abrikosov. In 1935 Fritz London published a very closely related work on magnetic flux quantization in superconductors. London's fluxoid can also be viewed as a quantum vortex.
Analog models of gravity are attempts to model various phenomena of general relativity using other physical systems such as acoustics in a moving fluid, superfluid helium, or Bose–Einstein condensate; gravity waves in water; and propagation of electromagnetic waves in a dielectric medium. These analogs serve to provide new ways of looking at problems, permit ideas from other realms of science to be applied, and may create opportunities for practical experiments within the analog that can be applied back to the source phenomena.
Polariton superfluid is predicted to be a state of the exciton-polaritons system that combines the characteristics of lasers with those of excellent electrical conductors. Researchers look for this state in a solid state optical microcavity coupled with quantum well excitons. The idea is to create an ensemble of particles known as exciton-polaritons and trap them. Wave behavior in this state results in a light beam similar to that from a laser but possibly more energy efficient.
David W. Snoke is a physics professor at the University of Pittsburgh in the Department of Physics and Astronomy. In 2006 he was elected a Fellow of the American Physical Society "for his pioneering work on the experimental and theoretical understanding of dynamical optical processes in semiconductor systems." In 2004 he co-wrote a controversial paper with prominent intelligent design proponent Michael Behe. In 2007, his research group was the first to report Bose-Einstein condensation of polaritons in a trap. David Snoke and theoretical physicist Jonathan Keeling recently published an article announcing a new era for polariton condensates saying that polaritons are arguably the "...best hope for harnessing the strange effects of quantum condensation and superfluidity in everyday applications."
The International Conference on Physics of Light–Matter Coupling in Nanostructures (PLMCN) is a yearly academic conference on various topics of semiconductor science and nanophotonics.
Yoshihisa Yamamoto is the director of Physics & Informatics Laboratories, NTT Research, Inc. He is also Professor (Emeritus) at Stanford University and National Institute of Informatics (Tokyo).
An optical transistor, also known as an optical switch or a light valve, is a device that switches or amplifies optical signals. Light occurring on an optical transistor's input changes the intensity of light emitted from the transistor's output while output power is supplied by an additional optical source. Since the input signal intensity may be weaker than that of the source, an optical transistor amplifies the optical signal. The device is the optical analog of the electronic transistor that forms the basis of modern electronic devices. Optical transistors provide a means to control light using only light and has applications in optical computing and fiber-optic communication networks. Such technology has the potential to exceed the speed of electronics, while conserving more power. The fastest demonstrated all-optical switching signal is 900 attoseconds, which paves the way to develop ultrafast optical transistors.
A polariton laser is a novel type of laser source that exploits the coherent nature of Bose condensates of exciton-polaritons in semiconductors to achieve ultra-low threshold lasing.
In physics, the exciton–polariton is a type of polariton; a hybrid light and matter quasiparticle arising from the strong coupling of the electromagnetic dipolar oscillations of excitons and photons. Because light excitations are observed classically as photons, which are massless particles, they do not therefore have mass, like a physical particle. This property makes them a quasiparticle.
Spin Optics Laboratory (SOLAB) is named after Igor Nikolaevich Uraltsev and located at the V. A. Fock Institute of Physics of Saint Petersburg State University. It is funded by the megagrant of Russian Federation government. Prof. Alexey Kavokin is the head of the Laboratory.
The semiconductor luminescence equations (SLEs) describe luminescence of semiconductors resulting from spontaneous recombination of electronic excitations, producing a flux of spontaneously emitted light. This description established the first step toward semiconductor quantum optics because the SLEs simultaneously includes the quantized light–matter interaction and the Coulomb-interaction coupling among electronic excitations within a semiconductor. The SLEs are one of the most accurate methods to describe light emission in semiconductors and they are suited for a systematic modeling of semiconductor emission ranging from excitonic luminescence to lasers.
Bose–Einstein condensation can occur in quasiparticles, particles that are effective descriptions of collective excitations in materials. Some have integer spins and can be expected to obey Bose–Einstein statistics like traditional particles. Conditions for condensation of various quasiparticles have been predicted and observed. The topic continues to be an active field of study.
Yasuhiko Arakawa is a Japanese physicist.
Bose–Einstein condensation of polaritons is a growing field in semiconductor optics research, which exhibits spontaneous coherence similar to a laser, but through a different mechanism. A continuous transition from polariton condensation to lasing can be made similar to that of the crossover from a Bose–Einstein condensate to a BCS state in the context of Fermi gases. Polariton condensation is sometimes called “lasing without inversion”.
Elisabeth Giacobino is a French physicist specialized in laser physics, nonlinear optics, quantum optics and super-fluidity. She is one of the pioneers of quantum optics and quantum information. She graduated from Pierre and Marie Curie University and started working at the French National Centre for Scientific Research, where she has spent the majority of her professional career. She has been an invited professor at New York University and University of Auckland. She has over 230 publications and over 110 invited presentations in international conferences. She has been the coordinator of four European projects and is a member of Academia Leopoldina as well as a fellow member of the European Physical Society, the European Optical Society and the Optical Society of America.
Hui Cao (曹蕙) is a Chinese American physicist who is the professor of applied physics, a professor of physics and a professor of electrical engineering at Yale University. Her research interests are mesoscopic physics, complex photonic materials and devices, with a focus on non-conventional lasers and their unique applications. She is an elected member of the US National Academy of Sciences and of the American Academy of Arts and Sciences.
Jonathan James Finley is a Professor of Physics at the Technical University of Munich in Garching, Germany, where he holds the Chair of Semiconductor Nanostructures and Quantum Systems. His focus is on quantum phenomena in semiconductor nanostructures, photonic materials, dielectric and metallic films, among others, for applications in quantum technology. At such, he made major contributions to the characterization and understanding of the optical, electronic and spintronic properties of quantum dots and wires both from group-IV and II-VI materials and oxides.
