January 31st, 2016 | by admin | published in News, Preprints, Quantum Computing
We introduce an always-on, exchange-only qubit made up of three localized semiconductor spins that offers a true “sweet spot” to fluctuations of the quantum dot energy levels. Both single- and two-qubit gate operations can be performed using only exchange pulses while maintaining this sweet spot. We show how to interconvert this qubit to other three-spin […]
November 5th, 2015 | by admin | published in News, Papers, Quantum Computing
Spin qubits composed of either one or three electrons are realized in a quantum dot formed at a Si/SiO_2-interface in isotopically enriched silicon. Using pulsed electron spin resonance, we perform coherent control of both types of qubits, addressing them via an electric field dependent g-factor. We perform randomized benchmarking and find that both qubits can […]
January 16th, 2015 | by admin | published in Highlights, News
We were asked to write a perspective for the Per Delsing group’s recent publication in Science: Catching the quantum sound wave Here’s the corresponding article: Propagating phonons coupled to an artificial atom
July 4th, 2014 | by admin | published in Featured, Highlights, Quantum Computing, Research
Superconducting circuits are exceptionally flexible, enabling many different devices from sensors to quantum computers. Separately, epitaxial semiconductor devices such as spin qubits in silicon offer more limited device variation but extraordinary quantum properties for a solid-state system. It might be possible to merge the two approaches, making single-crystal superconducting devices out of a semiconductor by […]
September 8th, 2013 | by admin | published in All, Highlights, Nanotechnology, Phonitons, Quantum Computing, Research
We show how long-lived and tunable acceptor impurity states in silicon nanomechanical cavities can play the role of a matter non-linearity for coherent phonons just as, e.g., the Josephson qubit plays in circuit-QED.
August 30th, 2013 | by admin | published in All, Nanotechnology, News, Papers, Phonitons, Quantum Computing
We describe a chip-based, solid-state analog of cavity-QED utilizing acoustic phonons instead of photons. We show how long-lived and tunable acceptor impurity states in silicon nanomechanical cavities can play the role of a matter nonlinearity for coherent phonons just as, e.g., the Josephson qubit plays in circuit QED. Both strong coupling (number of Rabi oscillations ≲100) and strong dispersive coupling (0.1–2 MHz) regimes can be reached in cavities in the 1–20-GHz range, enabling the control of single phonons, phonon-phonon interactions, dispersive phonon readout of the acceptor qubit, and compatibility with other optomechanical components such as phonon-photon translators. We predict explicit experimental signatures of the acceptor-cavity system.
August 9th, 2013 | by admin | published in All, News, Preprints, Quantum Computing
Two-tone spectroscopy of a superconducting transmon qubit in a cavity. We find evidence of strongly-coupled atomic physics in these man-made systems.
Superconducting qubits and circuits are a promising technology for a variety of applications, from exploration of physics to quantum information processing or particle detectors.
January 25th, 2013 | by admin | published in All, Blog, Preprints, Quantum Computing
We review and expand on previous work that treats relaxation physics of low-lying excited states in ideal, single electron, silicon quantum dots in the context of quantum computing. These states are of three types: orbital, valley, and spin. The relaxation times depend sensitively on system parameters such as the dot size and the external magnetic […]
April 17th, 2012 | by admin | published in All, News, Phonitons
Could the Next World-Changing Technology Emerge From UMD? (Not exactly how we would hype it, but we appreciate the support!) Phonitons as a Sound-based Analogue of Cavity Quantum Electrodynamics Charles George Tahan, Rousko Todorov Hristov, Oney O. Soykal Researchers at the University of Maryland and the National Security Agency (NSA) have developed the analog of […]
November 28th, 2011 | by admin | published in All, Blog, Featured, Highlights, Nanotechnology, Papers, Phonitons, Research
This work explores the possibility of a new, man-made quantum object: a hybridization of a localized, long-lived phonon (a quantum of sound) and a matter excitation. That this is possible is not obvious.