Bose Einstein Condensation Research Papers (original) (raw)

With such a general model, one cannot obtain numerical results, but one can obtain general results which appear to correspond to some of the peculiar properties of liquid helium. Eq. (1) is not the exact Hamiltonian; it can be derived... more

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- Condensed Matter Physics, Superfluidity, Bose Einstein Condensation, HE
- by Stephane Ouvry
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- Bose Einstein Condensation, Models, Mathematical Sciences, Physical sciences
- by Patrick Dasgupta
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- Physics, Multidisciplinary, Bose Einstein Condensation, Current Science
- by Luigi Maxmilian Caligiuri
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- Quantum Physics, Bose Einstein Condensation, Gravity Model

The hyperdimensional Infinite Spiral Staircase Theory (-ISST theory‖) rests on two basic premises. The first one posits a hyperdimension layer in all matter and biomatter systems, from particles to galaxies. The second predicates that, since the hyperdimension is triune, the sub-Planckian and superluminous energy that organizes it is in essence linked to consciousness. ISST theory postulates that all psi phenomena as well as altered states of consciousness instantiate the dynamics of the hyperdimensional syg-energy. Namely, they are driven by attraction, resonance and harmony, and defy locality. This essay trys to tackle the strangest dynamics of heightened consciousness, a type of mind coherence shown in telepathic-harmonic fields, in which a group experiences a shared mind-state, and compare them with the remarkable quantum coherence in Bose-Einstein condensates (-BCEs‖) as well as the resonances and scale-invariance found in natural systems. These dynamics are essentially linked to a higher and more harmonic organizational order, based on wave resonance, whether the atoms' waves all getting in phase and sharing the same quantum state as in BECs, or the periodic and logarithmic recurrence of the frequency of proton at higher scales. The author argues that they instantiate the workings of the enmeshed Rhythm-hyperdimension (hypertime) and Center-hyperdimension (hyperspace). Further, the author will explore a hypothetic texture of the hyperdimension as both layered and honeycombed.

In this paper, we examine the possibility of generating bright and dark solitons, as well as multi-pulse solitary waves in Bose–Einstein condensates. Starting from the linear limit of the problem, where such solutions are known explicitly, we use 'dynamic continuation' through the temporal variation of the scattering length, which can be realized in experiments upon using external time-dependent magnetic fields. We examine the stability of the resulting solutions both through direct numerical simulations and through numerical continuation of the relevant steady states and linear stability analysis. Analytical results, illustrating the nature of the bifurcation of the nonlinear solutions, are found to be in good agreement with the numerical findings. (Some figures in this article are in colour only in the electronic version)

- by Augusto Silveira Rodrigues and +2
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- Bose Einstein Condensation

Although the postulate of " photon-having-zero-rest-mass " became over the years a sort of " dogma " , routinely repeated in thousands of physics textbooks and scientific articles, great physicists like two " fathers " of Quantum Mechanics: Erwin Schrödinger and Louis De Broglie, never believed that photons were really " massless " at rest, and many other remarkable physicists challenged this conviction as well. In recent years (2001-2005), the experiments through which Lene Westengarten Hau succeeded in slowing down, stopping, and making restart a laser light pulse by making it pass through optical molasses and ultra-cold sodium vapors of BEC (Bose-Einstein Condensates) can be interpreted as final and persuading evidence that photons –being both particles and e.m. waves-do possess a rest mas and they can be damped in " classical " and quantum ways as damped harmonic oscillators (classical) and superposing waves (QM). Therefore the speed of light is neither an universal constant (c), nor it is " invariant under Lorentz' transformations " , thereby destroying the 2 main pillars of Einstein's SR (Special Relativity). " There must be no barriers to freedom of inquiry. There is no place for dogma in science. The scientist is free, and must be free to ask any question, to doubt any assertion, to seek for any evidence, to correct any errors. " (J. Robert Oppenheimer)

- by Alberto Miatello
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- Condensed Matter Physics, Quantum Physics, Quantum Optics, Relativity

Sequel to my 2002. book Destiny Matrix

- by Jack Sarfatti and +3
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- Artificial Intelligence, Quantum Physics, Philosophy, Quantum Information

The aim of this introductory article is twofold. First, we aim to offer a general introduction to the theme of Bose-Einstein condensates, and briefly discuss the evolution of a number of relevant research directions during the last two decades. Second, we introduce and present the articles that appear in this Special Volume of Romanian Reports in Physics celebrating the conclusion of the second decade since the experimental creation of Bose-Einstein condensation in ultracold gases of alkali-metal atoms.

- by Boris Malomed and +1
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- Nonlinear Optics, Nonlinear dynamics, Bose Einstein Condensation, Solitons

In current physics there are various equations relating to variation of mass with velocity given by Thomson, Searle, Abraham, Lorentz , Bucherer and Einstein. The magnitudes of transverse and longitudinal masses given by different scientists are different. The common feature in equations is that they involve 'division by zero' when v=c, which is mathematically invalid operation. Thomson started it and following scientists continued deriving similar equations i.e. involving 'division by zero'. Initially Lorentz had given equation of transverse mass m T = m rest , where is undetermined factor or coefficient differing from unity by quantity of the order v 2 /c 2. Then value of was regarded as unity. In all practical purposes the transverse mass given by Lorentz is considered and value of is assumed to be unity. Einstein also derived equation of transverse mass (m T =m rest) but in calculation of rest mass energy (E rest =Mrest c 2) ignoring his own equation and used equation of transverse mass given by Lorentz (mT =mrest). This perception sets upper limit of velocity of any object, and have experimental support till date. Nevertheless, this aspect needs to be checked over wide range of parameters i.e. for various bodies approaching to speed of light. Thus an attempt is made to derive an alternate equation describing exponential variation of mass with velocity, M = M rest exp(Qv 2 /2c 2), which does not involve division by zero. Thus, 'motion and formation of universe are two simultaneous events' The value of coefficient Q is empirically calculated and is such that predictions of exponential equation and relativistic equation are same. The new equation predicts up to velocities 0.07c, this equation and Lorentz's equation give exactly similar results. Further at 0.1c , both equations give same results if value of Q is 1.0034. In LHC the protons are observed to move with speed v=0.99999999c then value of Q is turns out to be 17.7274. Nobody can move with speed of light , so under the condition (v approaches c) the value of Q is exceptionally-2 high. The eq.(30) never predicts inconsistent results i.e. undefined, infinite or imaginary mass. This equation would be immensely useful, if the new perceptions like variability of speed of light and superluminal velocity etc. have some experimental justification. At least the new exponential equation gives same results as Lorentz's equation does up to velocity 0.04c or 1.2x10 7 m/s. Roger's experiment confirms the Lorentz equation (with =1) to within 1% .

- by ajay sharma
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- Bose Einstein Condensation

(The paper has an additional coauthor: Thomasz Sowinski; the system does not allow to add this name)
Originally, the Hubbard model was derived for describing the behavior of strongly correlated electrons in solids. However, for over a decade now, variations of it have also routinely been implemented with ultracold atoms in optical lattices, allowing their study in a clean, essentially defect-free environment. Here, we review some of the vast literature on this subject, with a focus on more recent non-standard forms of the Hubbard model. After giving an introduction to standard (fermionic and bosonic) Hubbard models, we discuss briefly common models for mixtures, as well as the so-called extended Bose–Hubbard models, that
include interactions between neighboring sites, next-neighbor sites, and so on. The main part of the review discusses the importance of additional terms appearing when refining the tight-binding approximation for the original physical Hamiltonian. Even when restricting the models to the lowest Bloch band is justified, the standard approach neglects the density-induced tunneling (which has the same origin as the usual on-site interaction). The importance of these contributions is discussed for both contact and dipolar interactions. For sufficiently strong interactions, the effects related to higher Bloch bands also become important even for deep optical lattices. Different approaches that aim at incorporating these effects, mainly via dressing the basis, Wannier functions with interactions, leading to effective, density-dependent Hubbard-type models, are reviewed. We discuss also examples of Hubbard-like models that explicitly involve higher p orbitals, as well as models that dynamically couple spin and orbital degrees of freedom. Finally, we review mean-field nonlinear Schrödinger models of the Salerno type that share with the non-standard Hubbard models nonlinear coupling between the adjacent sites. In that part, discrete solitons are the main subject of consideration. We conclude by listing some open problems, to be addressed in the future.

- by Boris Malomed and +1
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- Bose Einstein Condensation, Solitons, Cold Atom, Optical Lattice, Bose Hubbard Model
- by Jon Nilsen
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- Thermodynamics, Quantum Mechanics, Quantum Monte Carlo, Bose Einstein Condensation

This thesis presents an experimental study of hydrodynamical phenomena of a laser propagating nonlinearly. For a medium presenting an intensity-dependent refractive index, and in the frame of the paraxial approximation, the intensity of the laser beam is equivalent to a density of a fluid, the propagation direction is seen as a time evolution of the fluid as well as the phase gradient of the laser beam defines a flow velocity and the nonlinear refractive index change allows defining a sound velocity of the fluid. Under this analogy, we call the propagating laser beam a fluid of light. In this thesis, we provide a study of the superfluidity concept of a fluid of light in a self-defocusing regime of the nonlinearity. It is defined as the absence of diffraction when the fluid of light encounters an obstacle. The parameters which control the superfluid transition are: the flow velocity as well as the sound velocity. They are monitored respectively through the wave vector and the intensity of the laser beam. In the frame of this analogy, we also present in this manuscript a study of vortex shedding regime as a result of the interaction between the fluid of light and the obstacle. Here, the obstacle is considered being strong. When twice the flow velocity at the poles of the obstacle is larger than the sound velocity, pairs of vortex/anti-vortex are emitted demonstrating a hydrodynamical behaviour of the fluid of light. In order to underline the nonlinear refractive index change, we also report in this thesis a study of the photorefractive nonlinearity using the self-phase modulation effect.

- by Omar Boughdad
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- Nonlinear Optics, Superfluidity, Vortex dynamics, Bose Einstein Condensation

Raw and unedited notes and considerations on R. Penrose and S. Hameroff's Orchestrated Objective Reduction Theory, Dr. Anirban Bandyopadhyay studies, Jürg Fröhlich Bose-Einstein condensation implications, Karthikeyan Marimuthu and Raj... more

This article offers a comprehensive survey of results obtained for solitons and complex nonlinear wave patterns supported by nonlinear lattices (NLs), which represent a spatially periodic modulation of the local strength and sign of the nonlinearity, and their combinations with linear lattices. A majority of the results obtained, thus far, in this field and reviewed in this article are theoretical. Nevertheless, relevant experimental settings are also surveyed, with emphasis on perspectives for implementation of the theoretical predictions in the experiment. Physical systems discussed in the review belong to the realms of nonlinear optics (including artificial optical media, such as photonic crystals, and plasmonics) and Bose-Einstein condensation. The solitons are considered in one, two, and three dimensions. Basic properties of the solitons presented in the review are their existence, stability, and mobility. Although the field is still far from completion, general conclusions can be drawn. In particular, a novel fundamental property of one-dimensional solitons, which does not occur in the absence of NLs, is a finite threshold value of the soliton norm, necessary for their existence. In multidimensional settings, the stability of solitons supported by the spatial modulation of the nonlinearity is a truly challenging problem, for theoretical and experimental studies alike. In both the one-dimensional and two-dimensional cases, the mechanism that creates solitons in NLs in principle is different from its counterpart in linear lattices, as the solitons are created directly, rather than bifurcating from Bloch modes of linear lattices.

The failure of the " Dark " Universe to explain observed astrophysical phenomenon has created a vacuum for cosmology. One attempt to fill this involves a radical concept of using Bose-Einstein Condensate (BEC). While it meets some of the limited criteria, it fails on multiple levels of basic physical needs and violates the laws of thermodynamics in a Big Bang Cosmological paradigm. Addressed here in brief are discussions of ultracold plasma, charge sequestration, and the EPEMC paradigm regarding ultracold states, such as superfluidity and superconductivity. BEC can be regarded therefore as a detailed boson-level study of the plasma superfluid interstellar medium, specifically on the retrieval end of the energy-mass cycle, rather than in an active galactic/gravitational side. There is simply no proof that BEC constitutes active " DM " , which is already explained with " charged " DM, that is: local matter, covert matter, hot dust/grains, and condensed matter. Furthermore, with any PEMC, the existence of DM is constrained out of the discussion which leaves BEC within a small category of interesting plasma sciences.

- by Shifu Careaga
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- Plasma Physics, Dark Matter, Dark Energy, Bose Einstein Condensation

PK Roy was a protege and lifelong friend of Satyendra Nath Bose. He did his PhD in particle physics under Abdus Salam, the future Nobel laureate, at Imperial College in London from 1957 to 2959. He was also a brilliant Marxist, but one who followed the Trotskyist rather than the dominant Stalinist line. He was slowly and painfully handicapped by a degenerative disease and died at age 50 from the effects of the misguided cure. This article traces his work in physics against the broader background of the university, the city, and the Bengali culture he so loved. This article originated as a short contribution to "CU Physics 100," a book of retrospective essays that Calcutta University published in early 2016 to mark the 100th anniversary of physics at the university.

- by Wes Ervin
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- Particle Physics, Indian studies, Dialectical Materialism, Bose Einstein Condensation

Recent experimental and theoretical advances in the creation and description of bright matter wave solitons are reviewed. Several aspects are taken into account, including the physics of soliton train formation as the nonlinear Fresnel diffraction, soliton-soliton interactions, and propagation in the presence of inhomogeneities. The generation of stable bright solitons by means of Feshbach resonance techniques is also discussed.

This paper introduces a quasiequilibrium one-dimensional Bose-Einstein condensation of photons trapped in a microtube. Light modes with a cutoff frequency (a photon's " mass ") interact through different processes of absorption, emission, and scattering on molecules and atoms. In this paper we study the conditions for the one-dimensional condensation of light and the role of photon-photon interactions in the system. The technique in use is the Matsubara Green's functions formalism modified for the quasiequilibrium system under study.

- by Alex Kruchkov
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- Quantum Optics, Bose Einstein Condensation, Photons, Bose Einstein Condensates

We explore the effect of mutual gravitational interaction between ultra-cold gas atoms on the dynamics of Bose-Einstein condensates (BEC). Small amplitude oscillation of BEC is studied by applying variational technique to reduce the Gross-Pitaevskii equation, with gravity included, to the equation of motion of a particle moving in a potential. According to our analysis, if the s-wave scattering length can be tuned to zero using Feshbach resonance for future BEC with occupation numbers as high as approx1020\approx 10^{20}approx1020, there exists a critical ground state occupation number above which the BEC is unstable, provided that its constituents interact with a 1/r31/r^3 1/r3 gravity at short scales.

- by Patrick Dasgupta
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- Bose Einstein Condensation

Plato as Apollo. // Платон как Аполлон.

- by Oleg Yermakov
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- Ancient Egyptian Religion, History, Ancient History, Evolutionary Biology

- by Arnaldo Gammal
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- Bose Einstein Condensation, Numerical Simulation, Mathematical Sciences, Solitons

Report for an Intership at the ILP in Hamburg on a bosonic and fermionic mixture.

- by Chiara Decaroli
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- Quantum Optics, Quantum Mechanics, Bose Einstein Condensation
- by Aranya Bhattacherjee
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- Quantum Optics, Bose Einstein Condensation, Normal Modes, Mechanical systems
- by haider hadi
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- Quantum Physics, Particle Physics, Bose Einstein Condensation, Dimensional Analysis

A theoretical study of interacting bosons in a periodic optical lattice is presented. Instead of the commonly used tight-binding approach (applicable near the Mott insulating regime of the phase diagram), the present work starts from the exact single-particle states of bosons in a cubic optical lattice, satisfying the Mathieu equation, an approach that can be particularly useful at large boson fillings. The effects of short-range interactions are incorporated using a self-consistent Hartree- Fock approximation, and predictions for experimental observables such as the superfluid transition temperature, condensate fraction, and boson momentum distribution are presented.

- by Qin-Qin Lu and +1
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- Theoretical Physics, Atomic Physics, Atomic and Molecular Physics, Bose Einstein Condensation

Cavity-optomechanics, a rapidly developing area of research, has made a remarkable progress. A
stunning manifestation of optomechanical phenomena is in exploiting the mechanical effects of
light to couple the optical degree of freedom with mechanical degree of freedom. In this report,
we investigate the controlled bistable dynamics of such hybrid optomechanical system composed
of cigar-shaped Bose-Einstein condensate (BEC) trapped inside high-finesse optical cavity with
one moving-end mirror and is driven by a single mode optical field. The numerical results provide
evidence for controlled optical bistability in optomechanics using transverse optical field which
directly interacts with atoms causing the coupling of transverse field with momentum side modes,
exited by intra-cavity field. This technique of transverse field coupling is also used to control
bistable dynamics of both moving-end mirror and BEC. The report provides an understanding
of temporal dynamics of moving-end mirror and BEC with respect to transverse field. Moreover,
dependence of effective potential of the system on transverse field has also been discussed. To
observe this phenomena in laboratory, we have suggested a certain set of experimental parameters.
These findings provide a platform to investigate the tunable behavior of novel phenomenon like
electromagnetically induced transparency and entanglement in hybrid systems.

- by Kashif Ammar Yasir
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- Quantum Optics, Quantum Chaos, Bose Einstein Condensation

We investigate finite-number effects in collisions between two states of an initially well-known number of identical bosons with contact interactions, oscillating in the presence of harmonic confinement in one dimension. We investigate two N/2 (interacting) ground states, which are initially displaced from the trap center, and the effects of varying interaction strength. The numerics focus on the simplest case of N=4. In the noninteracting case, such a system would display periodic oscillation with a half harmonic oscillator period (due to the left-right symmetry). With the addition of contact interactions between the bosons, collisions generate entanglement between each of the states and distribute energy into other modes of the oscillator. We study the system numerically via an exact diagonalization of the Hamiltonian with a finite basis, investigating left-right number uncertainty as our primary measure of entanglement. Additionally, we study the time evolution and equilibration of the single-body von Neumann entropy for both the attractive and repulsive cases. We identify parameter regimes for which attractive interactions create behavior qualitatively different from that of repulsive interactions, due to the presence of bound states (quantum solitons), and explain the processes behind this.

- by S. A. Gardiner and +1
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- Bose Einstein Condensation, Quantum entanglement, Ultracold Quantum Gases
- by Paolo Peralta
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- Bose Einstein Condensation

A galactic halo of dark matter is considered as a weakly interacting dilute Bose gas. The halo involves a core, in which some bosons form Bose-Einstein condensate, while the others remain in the non-degenerate state. The non-degenerate component is described as a gas of elementary excitations in the Hartree--Fock--Bogolyubov approximation taking into account the overall quasiparticle energy spectrum. A cloud of non-condensed bosons surrounds the core. Numerical solutions to the equations describing a dark matter density distribution show that the halo radius grows significantly when the condensate particle number fraction decreases. At the same time the radius of the condensate core remains almost the same. If the halo has comparable-sized condensate core, the non-degenerate component gives only insignificant contributions to the dark matter density profile and rotation curves when confronted with the pure condensate models. This conclusion is caused by constraints on the scattering cross section to the mass of dark matter particles ratio obtained from the Bullet Cluster measurements. It is shown that bosons with masses m ~100 eV do not violate these constraints if they form relatively small condensate ``drops'' (with a radius of about 100 astronomical units) inside a halo consisting of non-condensed particles.

- by Iskander G . Abdullin
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- Cosmology (Physics), Dark Matter, Astrophysics, Bose Einstein Condensation

The problem of finding a microscopic theory of phase transitions across a critical point is a central unsolved problem in theoretical physics. We find a general solution to that problem and present it here for the cases of Bose–Einstein condensation (BEC) in an interacting gas and ferromagnetism in a lattice of spins, interacting via a Heisenberg or Ising Hamiltonian. For BEC, we present the exact, valid for the entire critical region, equations for the Greenʼs functions and order parameter, that is a critical-region extension of the Beliaev–Popov and Gross-Pitaevskii equations. For the magnetic phase transition, we find an exact theory in terms of constrained bosons in a lattice and obtain similar equations for the Greenʼs functions and order parameter. In particular, we outline an exact solution for the three-dimensional Ising model.

- by Vitaly Kocharovsky and +1
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- Bose Einstein Condensation, Phase Transitions, Critical phenomena, Ising Model

We study the thermodynamic condensation of microcavity polaritons using a realistic model of disorder in semiconductor quantum wells. This approach correctly describes the polariton inhomogeneous broadening in the low density limit, and treats scattering by disorder to all orders in the condensed regime. While the weak disorder changes the thermodynamic properties of the transition little, the effects of disorder in the condensed state are prominent in the excitations and can be seen in resonant Rayleigh scattering.

Thermodynamic properties of the one-dimensional (1D) quantum
well (QW) with miscellaneous permutations of the Dirichlet (D) and
Neumann (N) boundary conditions (BCs) at its edges in the perpen-
dicular to the surfaces electric field E are calculated. For the canonical
ensemble, analytical expressions involving theta functions are found
for the mean energy and heat capacity cV for the box with no applied
voltage. Pronounced maximum accompanied by the adjacent min-
imum of the specific heat dependence on the temperature T for the
pure Neumann QW and their absence for other BCs are predicted and
explained by the structure of the corresponding energy spectrum. Ap-
plied field leads to the increase of the heat capacity and formation of
the new or modification of the existing extrema what is qualitatively
described by the influence of the associated electric potential. A re-
markable feature of the Fermi grand canonical ensemble is, at any BC
combination in zero fields, a salient maximum of cV observed on the
T axis for one particle and its absence for any other number N of cor-
puscles. Qualitative and quantitative explanation of this phenomenon
employs the analysis of the chemical potential and its temperature de-
pendence for different N. It is proved that critical temperature Tcr of
the Bose-Einstein (BE) condensation increases with the applied volt-
age for any number of particles and for any BC permutation except the ND case at small intensities E what is explained again by the
modification by the field of the interrelated energies. It is shown that
even for the temperatures smaller than Tcr the total dipole moment
hPi may become negative for the quite moderate E . For either Fermi
or BE system, the influence of the electric field on the heat capacity is
shown to be suppressed with N growing. Different asymptotic cases
of, e.g., the small and large temperatures and low and high voltages
are derived analytically and explained physically. Parallels are drawn
to the similar properties of the 1D harmonic oscillator, and similarities
and differences between them are discussed.

- by Oleg Olendski
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- Thermodynamics, Bose Einstein Condensation, Boundary Conditions, Quantum Wells

The condensation of the spinless ideal charged Bose gas in the presence of a magnetic field is revisited as a first step to tackle the more complex case of a molecular condensate, where several degrees of freedom have to be taken into account.
In the charged bose gas, the conventional approach is extended to include the macroscopic occupation of excited kinetic states lying in the lowest Landau level, which plays an essential role in the case of large magnetic fields. In that limit, signatures of two diffuse phase transitions (crossovers) appear in the specific heat. In particular, at temperatures lower than the cyclotron frequency, the system behaves as an effectively one-dimensional free boson system, with the specific heat equal to (1/2) NkB and a gradual condensation at lower temperatures.
In the molecular case, which is currently in progress, we have studied the condensation of rotational levels in a two–dimensional trap within the Bogoliubov approximation, showing that multi–step condensation also occurs.

- by Rafael L Delgado
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- Mathematical Physics, Physics, Theoretical Physics, Quantum Physics

Satyendra Nath Bose in Indian Philately
Satyendra Nath Bose (1 January 1894 – 4 February 1974) was a Bengali physicist (Theoretical physics). He is acquainted with for his work on quantum mechanics in early 1920s, providing the foundation for Bose–Einstein statistics and the theory of the Bose–Einstein condensate. He was a Fellow of the Royal Society and he was awarded the Padma Vibhushan in 1954 by the Government of India.

- by Dr. Kalyan Chakraborti
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- Physics, Bose Einstein Condensation, Philately, Satyendranath Bose

Atomic matter waves, like electromagnetic waves, can be focused, reflected, guided and split by currently available passive atom-optical elements. However, the key for many applications of electromagnetic waves lies in the availability of amplifiers. These active devices allow small signals to be detected, and led to the development of masers and lasers. Although coherent atomic beams have been produced, matter wave amplification has not been directly observed. Here we report the observation of phase-coherent amplification of atomic matter waves. The active medium is a Bose-Einstein condensate, pumped by light that is far off resonance. An atomic wave packet is split off the condensate by diffraction from an optical standing wave, and then amplified. We verified the phase coherence of the amplifier by observing interference of the output wave with a reference wave packet. This development provides a new tool for atom optics and atom interferometry, and opens the way to the construction of active matter-wave devices.

- by David Pritchard
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- Pharmacology, Biochemistry, Bioinformatics, Evolutionary Biology