Now showing items 21-40 of 164

• #### Controlled Preparation and Detection of d-Wave Superfluidity in Two-Dimensional Optical Superlattices ﻿

(Institute of Physics, 2009)
$d$-wave Cooper pairs are believed to be the key for understanding the phenomenon of high-temperature superconductivity in cuprates. These superconductors are an example of the emergence of strong pairing in systems with ...
• #### Controlling Spin Exchange Interactions of Ultracold Atoms in Optical Lattices ﻿

(American Physical Society (APS), 2003)
We describe a general technique that allows one to induce and control strong interaction between spin states of neighboring atoms in an optical lattice. We show that the properties of spin exchange interactions, such as ...
• #### Cooling through Optimal Control of Quantum Evolution ﻿

(American Physical Society (APS), 2013)
Nonadiabatic unitary evolution with tailored time-dependent Hamiltonians can prepare systems of cold-atomic gases with various desired properties such as low excess energies. For a system of two one-dimensional quasicondensates ...
• #### Decay of superfluid currents in a moving system of strongly interacting bosons ﻿

(American Physical Society (APS), 2005)
We analyze the stability and decay of supercurrents of strongly interacting bosons on optical lattices. At the mean-field level, the system undergoes an irreversible dynamic phase transition, whereby the current decays ...
• #### Decoherence Dynamics in Low-Dimensional Cold Atom Interferometers ﻿

(American Physical Society (APS), 2007)
We report on a study of the dynamics of decoherence of a matter-wave interferometer, consisting of a pair of low-dimensional cold atom condensates at finite temperature. We identify two distinct regimes in the time dependence ...
• #### Density ripples in expanding low-dimensional gases as a probe of correlations ﻿

(American Physical Society (APS), 2009)
We investigate theoretically the evolution of the two-point density correlation function of a low-dimensional ultracold Bose gas after release from a tight transverse confinement. In the course of expansion thermal and ...
• #### Direct measurement of the Zak phase in topological Bloch bands ﻿

(Nature Publishing Group, 2013)
Geometric phases that characterize the topological properties of Bloch bands play a fundamental role in the band theory of solids. Here we report on the measurement of the geometric phase acquired by cold atoms moving in ...
• #### Disordered Bose-Einstein Condensates in Quasi-One-Dimensional Magnetic Microtraps ﻿

(American Physical Society (APS), 2004)
We analyze the effects of a random magnetic potential in a microfabricated waveguide for ultracold atoms. We find that the shape and position fluctuations of a current carrying wire induce a strong Gaussian correlated ...
• #### Dissipation and quantum phase transitions of a pair of Josephson junctions ﻿

(American Physical Society (APS), 2003)
A model system consisting of a mesoscopic superconducting grain coupled by Josephson junctions to two macroscopic superconducting electrodes is studied. We focus on the effects of Ohmic dissipation caused by resistive ...
• #### Dissipative Dynamics of a Driven Quantum Spin Coupled to a Bath of Ultracold Fermions ﻿

(American Physical Society (APS), 2013)
We explore the dynamics and the steady state of a driven quantum spin coupled to a bath of fermions, which can be realized with a strongly imbalanced mixture of ultracold atoms using currently available experimental tools. ...
• #### Dissipative Preparation of Spin Squeezed Atomic Ensembles in a Steady State ﻿

(American Physical Society (APS), 2013)
We present and analyze a new approach for the generation of atomic spin-squeezed states. Our method involves the collective coupling of an atomic ensemble to a decaying mode of an open optical cavity. We demonstrate the ...
• #### Double Quantum Dots in Carbon Nanotubes ﻿

(American Physical Society, 2010)
We study the two-electron eigenspectrum of a carbon-nanotube double quantum dot with spin-orbit coupling. Exact calculations are combined with a simple model to provide an intuitive and accurate description of single-particle ...
• #### Dynamical Crystallization in the Dipole Blockade of Ultracold Atoms ﻿

(American Physical Society (APS), 2010)
We describe a method for controlling many-body states in extended ensembles of Rydberg atoms, forming crystalline structures during laser excitation of a frozen atomic gas. Specifically, we predict the existence of an ...
• #### Dynamical Instability of the XY Spiral State of Ferromagnetic Condensates ﻿

(American Physical Society (APS), 2008)
We calculate the spectrum of collective excitations of the XY spiral state prepared adiabatically or suddenly from a uniform ferromagnetic F ! 1 condensate. For spiral wave vectors past a critical value, spin wave excitation ...
• #### The Dynamics and Prethermalization of One Dimensional Quantum Systems Probed Through the Full Distributions of Quantum Noise ﻿

(Institute of Physics, 2011)
Quantum noise correlations have been employed in several areas in physics including condensed matter, quantum optics and ultracold atom to reveal non-classical states of the systems. So far, such analysis mostly focused ...
• #### Dynamics of One-dimensional Bose Liquids: Andreev-like Reflection at Y-junctions and Absence of the Aharonov-Bohm Effect ﻿

(American Physical Society, 2008)
We study one dimensional Bose liquids of interacting ultracold atoms in the Y-shaped potential when each branch is filled with atoms. We find that the excitation packet incident on a single Y-junction should experience a ...
• #### Electron-phonon interaction in ultrasmall-radius carbon nanotubes ﻿

(American Physical Society (APS), 2005)
We perform analysis of the band structure, phonon dispersion, and electron-phonon interactions in three types of small-radius carbon nanotubes. We find that the s5,5d nanotube can be described well by the zonefolding method ...
• #### Engineering superfluidity in Bose-Fermi mixtures of ultracold atoms ﻿

(American Physical Society (APS), 2005)
We investigate many-body phase diagrams of atomic boson-fermion mixtures loaded in the two-dimensional optical lattice. Bosons mediate an attractive, finite-range interaction between fermions, leading to fermion pairing ...
• #### Enhanced Antiferromagnetic Exchange between Magnetic Impurities in a Superconducting Host ﻿

(American Physical Society (APS), 2014)
It is generally believed that superconductivity only weakly affects the indirect exchange between magnetic impurities. If the distance r between impurities is smaller than than the superconducting coherence length \((r ...