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Tuning single GaAs quantum dots in resonance with a rubidium vapor

Mon, 2011-02-14 16:18 - Daniel Rudolph
Date: 
2010-08-23
Author(s): 

N. Akopian, U. Perinetti, L. Wang, A. Rastelli, O. G. Schmidt, and V. Zwiller

Reference: 

Appl. Phys. Lett. 97, 082103 (2010)

URL: 

http://link.aip.org/link/doi/10.1063/1.3478232

We study single GaAs quantum dots with optical transitions that can be brought into resonance with the widely used D2 transitions of rubidium atoms. We achieve resonance by Zeeman or Stark shifting the quantum dot levels. We discuss an energy stabilization scheme based on the absorption of quantum dot photoluminescence in a rubidium vapor. This offers a scalable means to counteract slow spectral diffusion in quantum dots.

Single quantum dot nanowire photodetectors

Mon, 2011-02-14 16:16 - Daniel Rudolph
Date: 
2010-09-16
Author(s): 

M. P. van Kouwen, M. H. M. van Weert, M. E. Reimer, N. Akopian, U. Perinetti, R. E. Algra, E. P. A. M. Bakkers, L. P. Kouwenhoven, and V. Zwiller

Reference: 

Appl. Phys. Lett. 97, 113108 (2010)

URL: 

http://link.aip.org/link/doi/10.1063/1.3484962

Gate controlled Aharonov-Bohm-type oscillations from single neutral excitons in quantum rings

Mon, 2011-02-14 16:12 - Daniel Rudolph
Date: 
2010-08-11
Author(s): 

F. Ding, N. Akopian, B. Li, U. Perinetti, A. Govorov, F. M. Peeters, C. C. Bof Bufon, C. Deneke1, Y. H. Chen, A. Rastelli, O. G. Schmidt, and V. Zwiller

Reference: 

Phys. Rev. B 82, 075309 (2010)

URL: 

http://link.aps.org/doi/10.1103/PhysRevB.82.075309

Wide InP superlattice wires with Wurtzite/Zincblende segments are type-II whereas narrower wires become type-I: An atomistic pseudopotential calculation

Mon, 2011-02-14 16:09 - Daniel Rudolph
Date: 
2010-09-01
Author(s): 

Lijun Zhang, Jun-Wei Luo, Alex Zunger, Nika Akopian, Val Zwiller, and Jean-Christophe Harmand

Reference: 

Nanoletters 4055, 10 (2010)

URL: 

http://dx.doi.org/10.1021/nl102109s

Nanowire-superlattices with different structural phases along the nanowire direction, such as wurtzite (WZ) and zincblende (ZB) forms of the same compound, often exhibit a “type II” band-alignment with electrons on ZB and holes on WZ. This is a material property of most of III−V semiconductors.

Universal Dynamical Decoupling of a Single Solid-State Spin from a Spin Bath

Mon, 2011-02-14 16:00 - Daniel Rudolph
Date: 
2010-09-09
Author(s): 

G. de Lange, Z. H. Wang, D. Ristè, V. V. Dobrovitski and R. Hanson

Reference: 

Science 330, 60 (2010)

URL: 

http://www.sciencemag.org/content/330/6000/60.abstract

Controlling the interaction of a single quantum system with its environment is a fundamental challenge in quantum science and technology. We strongly suppressed the coupling of a single spin in diamond with the surrounding spin bath by using double-axis dynamical decoupling. The coherence was preserved for arbitrary quantum states, as verified by quantum process tomography. The resulting coherence time enhancement followed a general scaling with the number of decoupling pulses.

Reentrance Effect in Macroscopic Quantum Tunneling and Nonadiabatic Josephson Dynamics in d-Wave Junctions

Mon, 2011-02-14 15:54 - Daniel Rudolph
Date: 
2010-09-16
Author(s): 

J. Michelsen and V. S. Shumeiko

Reference: 

Phys. Rev. Lett. 105, 127001 (2010)

URL: 

http://link.aps.org/doi/10.1103/PhysRevLett.105.127001

Nonadiabatic Josephson dynamics in junctions with in-gap quasiparticles

Mon, 2011-02-14 15:51 - Daniel Rudolph
Date: 
2010-10-01
Author(s): 

J. Michelsen and V. S. Shumeiko

Reference: 

Low Temp. Phys. 36, 925 (2010)

URL: 

http://link.aip.org/link/doi/10.1063/1.3516470

Analysis of a tunable coupler for superconducting phase qubits

Mon, 2011-02-14 15:47 - Daniel Rudolph
Date: 
2010-09-28
Author(s): 

Ricardo A. Pinto, Alexander N. Korotkov, Michael R. Geller, Vitaly S. Shumeiko, John M. Martinis

Reference: 

Phys. Rev. B 82, 104522 (2010)

URL: 

http://link.aps.org/doi/10.1103/PhysRevB.82.104522

Floquet theory of Cooper pair pumping

Mon, 2011-02-14 15:38 - Ingo Kamleitner
Date: 
2011-06-06
Author(s): 

A. Russomanno, S. Pugnetti, V. Brosco, and R. Fazio

Reference: 

Phys. Rev. B 83, 214508 (2011)

URL: 

http://link.aps.org/doi/10.1103/PhysRevB.83.214508

We derive a general formula for the charge pumped in a superconducting nanocircuit. Our expression generalizes previous results in several ways; it is applicable in both the adiabatic and in the nonadiabatic regimes and it takes into account also the effect of an external environment. More specifically, by applying Floquet theory to Cooper pair pumping, we show that under a cyclic evolution the total charge transferred through the circuit is proportional to the derivative of the associated Floquet quasi-energy with respect to the superconducting phase difference.

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