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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

Free standing beams containing a two-dimensional electron system are shaped from a GaAs/AlGaAs heterostructure. Quantum point contacts and (double) quantum dots are laterally defined using metal top gates. We investigate the electronic…

Mesoscale and Nanoscale Physics · Physics 2010-06-17 C Rossler , M Bichler , D Schuh , W Wegscheider , S Ludwig

We propose a novel mechanism for creating a qubit based on a tight knot, that is a nano-quantum wire system so small and so cold as to be quantum coherent with respect to curvature-induced effects. To establish tight knots as legitimate…

Quantum Physics · Physics 2017-03-21 Victor Atanasov , Rossen Dandoloff

We consider two interacting electrons in a semiconductor quantum dot structure which consists of a small dot within a larger dot, and demonstrate a singlet-triplet filtering mechanism which involves spin-dependent resonances and can…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 G. Giavaras , J. H. Jefferson , M. Fearn , C. J. Lambert

The prospect of coupling a two-dimensional (2D) semiconductor heterostructure to a superconductor opens new research and technology opportunities, including fundamental problems in mesoscopic superconductivity, scalable superconducting…

The interaction between two quantum bits enables entanglement, the two-particle correlations that are at the heart of quantum information science. In semiconductor quantum dots much work has focused on demonstrating single spin qubit…

Mesoscale and Nanoscale Physics · Physics 2011-03-14 Danny Kim , Samuel G. Carter , Alex Greilich , Allan Bracker , Daniel Gammon

We calculate the charge susceptibility and the linear and differential conductances of a double quantum dot coupled to two metallic reservoirs both at equilibrium and when the system is driven away from equilibrium. This work is motivated…

Mesoscale and Nanoscale Physics · Physics 2018-10-16 V. Talbo , M. Lavagna , T. Q. Duong , A. Crépieux

We experimentally characterize a quantum photonic gate that is capable of converting multiqubit entangled states while acting only on two qubits. It is an important tool in large quantum networks, where it can be used for re-wiring of…

We present a highly controllable double quantum dot device based on bilayer graphene. Using a device architecture of interdigitated gate fingers, we can control the interdot tunnel coupling between 1 to 4 GHz and the mutual capacitive…

In the emerging field of quantum computation and quantum information, superconducting devices are promising candidates for the implementation of solid-state quantum bits or qubits. Single-qubit operations, direct coupling between two…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 I. Chiorescu , P. Bertet , K. Semba , Y. Nakamura , C. J. P. M. Harmans , J. E. Mooij

A double quantum dot is formed in a graphene nanoribbon device using three top gates. These gates independently change the number of electrons on each dot and tune the inter-dot coupling. Transport through excited states is observed in the…

Mesoscale and Nanoscale Physics · Physics 2010-05-13 Xing Lan Liu , Dorothee Hug , Lieven M. K. Vandersypen

It was proposed that a double quantum dot can be used to be a detector of spin bias. Electron transport through a double quantum dot is investigated theoretically when a pure spin bias is applied on two conducting leads contacted to the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Qing-feng Sun , Yanxia Xing , Shun-Qing Shen

We study photon-photon correlations and entanglement generation in a one-dimensional waveguide coupled to two qubits with an arbitrary spatial separation. We develop a novel Green function method to study vacuum-mediated qubit-qubit…

Quantum Physics · Physics 2013-03-14 Huaixiu Zheng , Harold U. Baranger

Extremely long coherence times, excellent single-qubit gate fidelities and two-qubit logic have been demonstrated with silicon metal-oxide-semiconductor spin qubits, making it one of the leading platforms for quantum information processing.…

Mesoscale and Nanoscale Physics · Physics 2020-01-14 H. G. J. Eenink , L. Petit , W. I. L. Lawrie , J. S. Clarke , L. M. K. Vandersypen , M. Veldhorst

The current work investigates the performance of dual-gate GaAs-nanowire FET as a charge-qubit device operating at room temperature. In compatibility with the state-of-the-art classical bit technology, it is shown that the single gate of a…

Quantum Physics · Physics 2023-01-31 Basudev Nag Chowdhury , Sanatan Chattopadhyay

A spin filtering device using quantum spin interference is theoretically proposed in a GaAs/AlGaAs electron gas that has both Rashba and Dresselhaus spin-orbit couplings. The device achieves polarized electron currents by separating spin up…

Mesoscale and Nanoscale Physics · Physics 2015-03-19 Benjamin Santos , Ernesto Medina , Alexander López , Bertrand Berche

We present a method to enact a deterministic, measurement-free, optically generated controlled-phase gate on two qubits defined by single electrons trapped in large-area quantum dots in a planar microcavity. This method is robust to optical…

Quantum Physics · Physics 2009-10-28 T. D. Ladd , Y. Yamamoto

A quantum dot (QD) system provides various quantum physics of nanostructures. So far, many types of semiconductor QD structures have been fabricated and investigated experimentally and analyzed theoretically. Presently, QD systems have…

Mesoscale and Nanoscale Physics · Physics 2022-09-05 Tetsufumi Tanamoto , Tomosuke Aono

Recent advances in semiconductor spin qubits have achieved linear arrays exceeding ten qubits. Moving to two-dimensional (2D) qubit arrays is a critical next step to advance towards fault-tolerant implementations, but it poses substantial…

We describe in detail a set of ideas for implementing qubits, quantum gates and quantum gate networks in a semiconductor heterostructure device. Our proposal is based on an extension of the technology used for surface acoustic wave (SAW)…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 C. H. W. Barnes , J. M. Shilton , A. M. Robinson