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We present time-resolved charge sensing measurements on a GaAs double quantum dot with two proximal quantum point contact (QPC) detectors. The QPC currents are analyzed with cross-correlation techniques, which enables us to measure dot…

Mesoscale and Nanoscale Physics · Physics 2009-02-27 B. Küng , O. Pfäffli , S. Gustavsson , T. Ihn , K. Ensslin , M. Reinwald , W. Wegscheider

In order to employ solid state quantum dots as qubits, both a high degree of control over the confinement potential as well as sensitive charge detection are essential. We demonstrate that by combining local anodic oxidation with local…

Mesoscale and Nanoscale Physics · Physics 2011-06-13 C. Rössler , B. Küng , S. Dröscher , T. Choi , T. Ihn , K. Ensslin , M. Beck

Atomistic electronic structure calculations are performed to study the coherent inter-dot couplings of the electronic states in a single InGaAs quantum dot molecule. The experimentally observed excitonic spectrum [12] is quantitatively…

Mesoscale and Nanoscale Physics · Physics 2013-08-01 Muhammad Usman , Yui-Hong Matthias Tan , Hoon Ryu , Shaikh S. Ahmed , Hubert Krenner , Timothy B. Boykin , Gerhard Klimeck

We employ ultrafast pump-probe spectroscopy to directly monitor electron tunneling between discrete orbital states in a pair of spatially separated quantum dots. Immediately after excitation, several peaks are observed in the pump-probe…

We study quantum coherence in a semiconductor charge qubit formed from a GaAs double quantum dot containing a single electron. Voltage pulses are applied to depletion gates to drive qubit rotations and non-invasive state readout is achieved…

Mesoscale and Nanoscale Physics · Physics 2013-05-29 K. D. Petersson , J. R. Petta , H. Lu , A. C. Gossard

In this letter, we propose a quantized topological response in trapped 1D quantum gases. The experimental protocol for the response requires the application of an instant optical pulse to a half-infinite region in an asymptotically harmonic…

Quantum Gases · Physics 2023-04-05 Pengfei Zhang

Tunnel-coupled pairs of optically active quantum dots - quantum dot molecules (QDMs) - offer the possibility to combine excellent optical properties such as strong light-matter coupling with two-spin singlet-triplet ($S-T_0$) qubits having…

We report on the optical properties of single InAs/GaAs quantum dots emitting near the telecommunication O-band, probed via Coulomb blockade and non-resonant photoluminescence spectroscopy, in the presence of external electric and magnetic…

Mesoscale and Nanoscale Physics · Physics 2016-04-06 Luca Sapienza , Rima Al-Khuzheyri , Adetunmise Dada , Andrew Griffiths , Edmund Clarke , Brian D. Gerardot

We observe the low-lying excitations of a molecular dimer formed by two electrons in a GaAs semiconductor quantum dot in which the number of confined electrons is tuned by optical illumination. By employing inelastic light scattering we…

Mesoscale and Nanoscale Physics · Physics 2010-06-16 Achintya Singha , Vittorio Pellegrini , Aron Pinczuk , Loren N. Pfeiffer , Ken W. West , Massimo Rontani

We experimentally demonstrate a tunable hybrid qubit in a five-electron GaAs double quantum dot. The qubit is encoded in the (1,4) charge regime of the double dot and can be manipulated completely electrically. More importantly, dot…

Mesoscale and Nanoscale Physics · Physics 2016-03-02 Gang Cao , Hai-Ou Li , Guo-Dong Yu , Bao-Chuan Wang , Bao-Bao Chen , Xiang-Xiang Song , Ming Xiao , Guang-Can Guo , Hong-Wen Jiang , Xuedong Hu , Guo-Ping Guo

We report the investigation of a single quantum dot charge storage device. The device allows selective optical charging of a single dot with electrons, storage of these charges over timescales much longer than microseconds and reliable…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 D. Heiss , V. Jovanov , M. Caesar , M. Bichler , G. Abstreiter , J. J. Finley

We demonstrate the development of a double quantum dot with an integrated charge sensor fabricated in undoped GaAs/AlGaAs heterostructures using a double top-gated design. Based on the evaluation of the integrated charge sensor, the double…

Mesoscale and Nanoscale Physics · Physics 2015-06-22 Hai-Ou Li , Gang Cao , Ming Xiao , Jie You , Da Wei , Tao Tu , Guang-Can Guo , Hong-Wen Jiang , Guo-Ping Guo

We study optically single self-assembled quantum dots embedded within the wide quantum well of a mixed type quantum structure. We compare the steady state and pulsed photoluminescence spectra of these dots to those of previously studied…

Materials Science · Physics 2015-06-24 D. V. Regelman , E. Dekel , D. Gershoni , E. Ehrenfreund , W. V. Schoenfeld , P. M. Petroff

III-V semiconductor mid-infrared photodetectors based on intersubband transitions hold a great potential for ultra-high-speed operation up to several hundreds of GHz. In this work we exploit a ~350nm-thick GaAs/Al0.2Ga0.8As…

The integration of coherent quantum emitters with silicon photonic platforms essential for scalable quantum technologies. We demonstrate electrically controlled self-assembled quantum dots embedded in GaAs waveguides bonded onto a SiO2/Si…

Quantum networks are essential for realising distributed quantum computation and quantum communication. Entangled photons are a key resource, with applications such as quantum key distribution, quantum relays, and quantum repeaters. All…

We use a nanowire quantum dot to probe high-frequency current fluctuations in a nearby quantum point contact. The fluctuations drive charge transitions in the quantum dot, which are measured in real-time with single-electron detection…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 S. Gustavsson , I. Shorubalko , R. Leturcq , T. Ihn , K. Ensslin , S. Schön

Generating entangled graph states of qubits requires high entanglement rates, with efficient detection of multiple indistinguishable photons from separate qubits. Integrating defect-based qubits into photonic devices results in an enhanced…

We demonstrate experimentally a new technique to control the bandwidth and the type of frequency correlations (correlation, anticorrelation, and even uncorrelation) of entangled photons generated by spontaneous parametric downconversion.…

Quantum Physics · Physics 2009-11-13 M. Hendrych , M. Micuda , J. P. Torres

Semiconducting nanowires (NWs) are a versatile, highly tunable material platform at the heart of many new developments in nanoscale and quantum physics. Here, we demonstrate charge pumping, i.e., the controlled transport of individual…

Mesoscale and Nanoscale Physics · Physics 2015-09-07 S. d'Hollosy , M. Jung , A. Baumgartner , V. A. Guzenko , M. H. Madsen , J. Nygård , C. Schönenberger