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15.20.Ol Optical lattices

Emergence of coherence and the dynamics of quantum phase transitions

Thu, 2014-10-23 14:29 - Martin Kliesch
Date: 
2014-03-27 - 2014-10-23
Author(s): 

S. Braun, M. Friesdorf, S.S. Hodgman, M. Schreiber, J.P. Ronzheimer, A. Riera, M. del Rey, I. Bloch, J. Eisert, U. Schneider

Reference: 

arXiv:1403.7199

URL: 

http://arxiv.org/abs/1403.7199

Ideal negative measurements in quantum walks disprove theories based on classical trajectories

Tue, 2014-10-21 15:21 - Wolfgang Alt
Date: 
2015-01-20
Author(s): 

Carsten Robens, Wolfgang Alt, Dieter Meschede, Clive Emary, Andrea Alberti

Reference: 

Phys. Rev. X 5, 011003 (2015)

URL: 

http://dx.doi.org/10.1103/PhysRevX.5.011003

We report on a stringent test of the nonclassicality of the motion of a massive quantum particle, which propagates on a discrete lattice. Measuring temporal correlations of the position of single atoms performing a quantum walk, we observe a $6\sigma$ violation of the Leggett-Garg inequality. Our results rigorously excludes (i.e., falsifies) any explanation of quantum transport based on classical, well-defined trajectories.

Decoherence Models for Discrete-Time Quantum Walks and their Application to Neutral Atom Experiments

Tue, 2014-10-21 15:08 - Wolfgang Alt
Date: 
2014-12-19
Author(s): 

Andrea Alberti, Wolfgang Alt, Reinhard Werner, Dieter Meschede

Reference: 

New J. Phys. 16, 123052 (2014)

URL: 

http://dx.doi.org/10.1088/1367-2630/16/12/123052

We discuss decoherence in discrete-time quantum walks in terms of a phenomenological model that distinguishes spin and spatial decoherence. We identify the dominating mechanisms that affect quantum-walk experiments realized with neutral atoms walking in an optical lattice.

Crystallization in Ising quantum magnets

Tue, 2014-05-13 15:24 - Christian Gross
Date: 
2015-03-27
Author(s): 

Peter Schauß, Johannes Zeiher, Takeshi Fukuhara, Sebastian Hild, Marc Cheneau, Tommaso Macrì, Thomas Pohl, Immanuel Bloch, Christian Gross

Reference: 

Science 347, 1455–1458 (2015)

URL: 

http://www.sciencemag.org/content/347/6229/1455

Emergence of coherence and the dynamics of quantum phase transitions

Tue, 2014-05-13 15:21 - Christian Gross
Date: 
2015-03-24
Author(s): 

S. Braun, M. Friesdorf, S.S. Hodgman, M. Schreiber, J.P. Ronzheimer, A. Riera, M. del Rey, I. Bloch, J. Eisert, U. Schneider

Reference: 

PNAS 112, 3641–3646 (2015)

URL: 

http://www.pnas.org/content/112/12/3641

Observation of chiral currents with ultracold atoms in bosonic ladders

Tue, 2014-05-13 15:18 - Christian Gross
Date: 
2014-07-06
Author(s): 

M. Atala , M. Aidelsburger , M. Lohse, J. T. Barreiro , B. Paredes & I. Bloch

Reference: 

Nat. Phys. 10, 588–593 (2014)

URL: 

http://www.nature.com/nphys/journal/v10/n8/full/nphys2998.html

Electric quantum walks with individual atoms

Tue, 2014-01-28 20:38 - Tomas Rybar
Date: 
2013-05-07 - 2014-01-28
Author(s): 

Maximilian Genske, Wolfgang Alt, Andreas Steffen, Albert H. Werner, Reinhard F. Werner, Dieter Meschede, Andrea Alberti

Reference: 

Phys. Rev. Lett. 110, 190601

URL: 

http://prl.aps.org/abstract/PRL/v110/i19/e190601

We report on the experimental realization of electric quantum walks, which mimic the effect of an electric field on a charged particle in a lattice. Starting from a textbook implementation of discrete-time quantum walks, we introduce an extra operation in each step to implement the effect of the field. The recorded dynamics of such a quantum particle exhibits features closely related to Bloch oscillations and interband tunneling.

Ground-State Cooling of a Single Atom at the Center of an Optical Cavity

Mon, 2014-01-13 19:53 - Stephan Ritter
Date: 
2013-05-30
Author(s): 

A. Reiserer, C. Nölleke, S. Ritter, G. Rempe

Reference: 

Phys. Rev. Lett. 110, 223003 (2013)

URL: 

http://link.aps.org/doi/10.1103/PhysRevLett.110.223003

A single neutral atom is trapped in a three-dimensional optical lattice at the center of a high-finesse optical resonator. Using fluorescence imaging and a shiftable standing-wave trap, the atom is deterministically loaded into the maximum of the intracavity field where the atom-cavity coupling is strong. After 5 ms of Raman sideband cooling, the three-dimensional motional ground state is populated with a probability of (89+/-2)%.

In situ measurement of vacuum window birefringence by atomic spectroscopy

Wed, 2014-01-08 13:26 - Wolfgang Alt
Date: 
2013-12-13
Author(s): 

Andreas Steffen, Wolfgang Alt, Maximilian Genske, Dieter Meschede, Carsten Robens, Andrea Alberti

Reference: 

Review of Scientific Instruments 84, 126103 (2013)

URL: 

http://dx.doi.org/10.1063/1.4847075

We present an in situ method to measure the birefringence of a single vacuum window by means of microwave spectroscopy on an ensemble of cold atoms. Stress-induced birefringence can cause an ellipticity in the polarization of an initially linearly polarized laser beam. The amount of ellipticity can be reconstructed by measuring the differential vector light shift of an atomic hyperfine transition.

Optical lattice implementation scheme of a bosonic topological model with fermionic atoms

Tue, 2014-01-07 17:19 - Mari-Carmen Banuls
Date: 
2014-01-07
Author(s): 

Anne E. B. Nielsen, German Sierra, and J. Ignacio Cirac

Reference: 

arXiv:1311.7684 [cond-mat.str-el]

URL: 

http://arxiv.org/abs/1311.7684

We present a scheme to implement a Fermi-Hubbard-like model in ultracold atoms in optical lattices and analyze the topological features of its ground state. In particular, we show that the ground state for appropriate parameters has a large overlap with a lattice version of the bosonic Laughlin state at filling factor one half. The scheme utilizes laser assisted and normal tunnelling in a checkerboard optical lattice.

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