scholarly journals Bose-Einstein condensate and spontaneous breaking of conformal symmetry on Killing horizons II

2006 ◽  
Vol 47 (3) ◽  
pp. 032302 ◽  
Author(s):  
Valter Moretti
Keyword(s):  
Conformal Symmetry ◽  
Einstein Condensate ◽  
Spontaneous Breaking ◽  
Bose Einstein Condensate ◽  
Bose Einstein ◽  
Killing Horizons

scholarly journals A new type of half-quantum circulation in a macroscopic polariton spinor ring condensate

2015 ◽  
Vol 112 (9) ◽  
pp. 2676-2681 ◽  
Author(s):  
Gangqiang Liu ◽  
David W. Snoke ◽  
Andrew Daley ◽  
Loren N. Pfeiffer ◽  
Ken West
Keyword(s):  
Quantum State ◽  
Polarization Vector ◽  
Einstein Condensate ◽  
Spontaneous Breaking ◽  
Polarization Component ◽  
Bose Einstein Condensate ◽  
Ring Geometry ◽  
Bose Einstein ◽  
Simply Connected ◽  
Spin Flips

We report the observation of coherent circulation in a macroscopic Bose–Einstein condensate of polaritons in a ring geometry. Because they are spinor condensates, half-quanta are allowed in where there is a phase rotation of π in connection with a polarization vector rotation of π around a closed path. This half-quantum behavior is clearly seen in the experimental observations of the polarization rotation around the ring. In our ring geometry, the half-quantum state that we see is one in which the handedness of the spin flips from one side of the ring to the other side in addition to the rotation of the linear polarization component; such a state is allowed in a ring geometry but will not occur in a simply connected geometry. This state is lower in energy than a half-quantum state with no change of the spin direction and corresponds to a superposition of two different elementary half-quantum states. The direction of circulation of the flow around the ring fluctuates randomly between clockwise and counterclockwise from one shot to the next; this fluctuation corresponds to spontaneous breaking of time-reversal symmetry in the system. This type of macroscopic polariton ring condensate allows for the possibility of direct control of the circulation to excite higher quantized states and the creation of Josephson junction tunneling barriers.

scholarly journals Transport of a Single Cold Ion Immersed in a Bose-Einstein Condensate

2021 ◽  
Vol 126 (3) ◽  
Author(s):  
T. Dieterle ◽  
M. Berngruber ◽  
C. Hölzl ◽  
R. Löw ◽  
K. Jachymski ◽  
...  
Keyword(s):  
Einstein Condensate ◽  
Bose Einstein Condensate ◽  
Bose Einstein

scholarly journals Ultrafast electron cooling in an expanding ultracold plasma

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tobias Kroker ◽  
Mario Großmann ◽  
Klaus Sengstock ◽  
Markus Drescher ◽  
Philipp Wessels-Staarmann ◽  
...  
Keyword(s):  
Theoretical Models ◽  
Einstein Condensate ◽  
Direct Access ◽  
Electron Cooling ◽  
Plasma Dynamics ◽  
Strongly Coupled ◽  
Bose Einstein Condensate ◽  
Ultracold Plasma ◽  
Strongly Coupled Plasma ◽  
Bose Einstein

AbstractPlasma dynamics critically depends on density and temperature, thus well-controlled experimental realizations are essential benchmarks for theoretical models. The formation of an ultracold plasma can be triggered by ionizing a tunable number of atoms in a micrometer-sized volume of a 87Rb Bose-Einstein condensate (BEC) by a single femtosecond laser pulse. The large density combined with the low temperature of the BEC give rise to an initially strongly coupled plasma in a so far unexplored regime bridging ultracold neutral plasma and ionized nanoclusters. Here, we report on ultrafast cooling of electrons, trapped on orbital trajectories in the long-range Coulomb potential of the dense ionic core, with a cooling rate of 400 K ps−1. Furthermore, our experimental setup grants direct access to the electron temperature that relaxes from 5250 K to below 10 K in less than 500 ns.

scholarly journals Derivation of the Landau–Pekar Equations in a Many-Body Mean-Field Limit

2021 ◽  
Vol 240 (1) ◽  
pp. 383-417
Author(s):  
Nikolai Leopold ◽  
David Mitrouskas ◽  
Robert Seiringer
Keyword(s):  
Mean Field ◽  
Einstein Condensate ◽  
Back Reaction ◽  
Many Body ◽  
Field Limit ◽  
Mean Field Limit ◽  
Phonon Field ◽  
Bose Einstein Condensate ◽  
Weakly Couple ◽  
Bose Einstein

AbstractWe consider the Fröhlich Hamiltonian in a mean-field limit where many bosonic particles weakly couple to the quantized phonon field. For large particle numbers and a suitably small coupling, we show that the dynamics of the system is approximately described by the Landau–Pekar equations. These describe a Bose–Einstein condensate interacting with a classical polarization field, whose dynamics is effected by the condensate, i.e., the back-reaction of the phonons that are created by the particles during the time evolution is of leading order.

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