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Oral: Gustavo D. CipagautaDetuning-Control of Exciton Entanglement in Two Quantum Dots Coupled to a Photonic Mode
Co-authors: Karen M. Fonseca-Romero 14:45-15:00
Oral: Amir Capua
Direct Observation of Wavefunction Decoherence & Control over the Electronic Quantum State in a Room-Temperature InAs/InP Quantum Dot Semiconductor Optical Amplifier
Co-authors: Ouri Karni, Gadi Eisenstein, Vitalii Ivanov, Vitalii Sichkovskyi, Johann Peter Reithmaier
15:00-15:30Invited: Jonathan H. PrechtelCoherent Population Trapping on a Single Hole Spin in a Semiconductor Quantum Dot
Co-authors: Andreas V. Kuhlmann, Julien Houel, Arne Ludwig, Andreas D. Wieck, Richard J. Warburton
The coherence of an electron spin qubit in a semiconductor quantum dot (QD) is limited by the hyperfine interaction with the nuclear spins. Switching to a hole spin may bypass this problem. The hyperfine interaction of a pure heavy hole spin has a dipole-dipole term along the growth direction only such that the coupling to the nuclear spins is highly suppressed in an in-plane magnetic field . We explore here the extent to which this ideal limit can be achieved in practice using coherent population trapping (CPT), a quantum interference which arises between two ground states, here the hole spin states, and a common upper level, here the exciton state of an InGaAs quantum dot. CPT enables a precise spectroscopic measurement of the hole Zeeman splitting ZH and also a probe of hole spin decoherence. The long hole spin coherence enables us to achieve CPT dips of just 33 neV (8 MHz) width.
We find that ZH depends on vertical electric field, F. While ZH is QD-dependent, dZH/dF is largely the same for all QDs in our sample. We show that via this mechanism, charge noise results in significant hole spin dephasing in our good but imperfect device. The interaction with the nuclear spins is quantified by polarizing the nuclear spins optically, measuring ZH with CPT. In an in-plane magnetic field of 3 T, ZH remains the same (to within our error of 20 neV) even as the electron Zeeman energy changes by 12 eV. This demonstrates a remarkably effective decoupling of the hole spin from the nuclear spins.
 J. Fischer et al, Phys. Rev. B 78, 155329 (2008).15:30-15:45Oral: Carlos AntonMomentum Space Interferences as an Evidence of Remote Quantum Coherence of Condensates
Co-authors: Guilherme Tosi, Maria Dolores Martin, Zacharias Hatzopoulos, Georgios Konstantinidis, Peter Eldridge, Pavlos Savvidis, Carlos Tejedor, Luis Viña15:45-16:00Oral: Yves Leandre DelleyCoherent Spin Qubits in Optically Active InGaAs Quantum Dots
Co-authors: Wei-bo Gao, Aymeric Delteil, Priska Studer, Martin Kroner, Stefan Fält, Werner Wegscheider, Ataç İmamoğlu16:00-16:15Oral: John BradleyNano-Epitaxy as a Platform for Quantum Photonics
Co-authors: Andrew Foster, Andrey Krysa, Ben Royall, Paul Fry, Maurice Skolnick, Luke Wilson16:15-16:30Oral: Clemens Matthiesen
Measuring the Local Environment of a Quantum Dot
Co-authors: Megan Stanley, Jack Hansom, Claire Le Gall, Mete Atature