中关村论坛 256
题目: Superconducting Artificial Atom with Two-Degrees of Freedom
时间: 2014年01月21日 10:00
地点: M楼249会议室
报告人: Dr. Olivier Buisson
Institut Néel, CNRS and Université Joseph Fourier, F-38042 Grenoble, France
摘要报告：
Quantum mechanics was developed initially to describe properties of electrons in atoms. During the last decade, it has been shown that superconducting electrons dynamics inside nano-circuits follows quantum law at very low temperature. Thus these circuits appear as artificial atoms whose properties are not fixed by the number of electrons or atom nucleus but by electronics compounds (capacitance, inductance, tunnel barrier). These are adjustable during the nano-fabrication process. In addition, the artificial atom's quantum states can be readily manipulated by external magnetic flux or microwaves.
After an introduction on superconducting qubits based on anharmonic oscillators, I will present recent results obtained on artificial atoms with two degrees of freedom. Such device can verify three-level V-shaped or four-level diamond-shaped energy spectrum [1]. In addition, spectroscopy measurements have shown non-linear coupling between the two degrees of freedom, giving rise to frequency conversion [2] or cross-Kerr effect. We propose to use this cross-Kerr effect to realize a fast quantum “non-demolition” measurement with high fidelity [3].
[1] Non-linear coupling between the two oscillation modes of a dc-SQUID, F. Lecocq, et al, Phys. Rev. Lett. 107, 197002 (2011).
[2] Coherent Frequency Conversion in a Superconducting Artificial Atom with Two Internal Degrees of Freedom, F. Lecocq, et al, Phys. Rev. Lett. 108, 107001 (2012).
[3] Ultrafast QND measurements based on diamond-shape artificial atom. I. Diniz, et al, Phys. Rev. A 87, 033837 (2013).
报告人简介：
Dr. Olivier Buisson is “Directeur de recherche” at the CNRS. He graduated from Institute National Polytechnic of Grenoble in 1987 and received his PhD from Joseph Fourier University in 1990. After working on plasma modes in superconducting 1D and 2D systems, he initiated in Grenoble the studies on Quantum Superconducting Circuits. Main results have concerned Macroscopic Quantum tunneling in a dc SQUID, multilevel quantum dynamics, tunable coupling between a charge and a phase qubit, Camelback phase qubit.
Current scientific activity includes quantum phase slip in Josephson chains, artificial atoms with two dimensional degrees of freedom, fast QND read out on a phase qubit.
报告邀请人：郑东宁 研究员（8264-9187）
摘要报告：
Quantum mechanics was developed initially to describe properties of electrons in atoms. During the last decade, it has been shown that superconducting electrons dynamics inside nano-circuits follows quantum law at very low temperature. Thus these circuits appear as artificial atoms whose properties are not fixed by the number of electrons or atom nucleus but by electronics compounds (capacitance, inductance, tunnel barrier). These are adjustable during the nano-fabrication process. In addition, the artificial atom's quantum states can be readily manipulated by external magnetic flux or microwaves.
After an introduction on superconducting qubits based on anharmonic oscillators, I will present recent results obtained on artificial atoms with two degrees of freedom. Such device can verify three-level V-shaped or four-level diamond-shaped energy spectrum [1]. In addition, spectroscopy measurements have shown non-linear coupling between the two degrees of freedom, giving rise to frequency conversion [2] or cross-Kerr effect. We propose to use this cross-Kerr effect to realize a fast quantum “non-demolition” measurement with high fidelity [3].
[1] Non-linear coupling between the two oscillation modes of a dc-SQUID, F. Lecocq, et al, Phys. Rev. Lett. 107, 197002 (2011).
[2] Coherent Frequency Conversion in a Superconducting Artificial Atom with Two Internal Degrees of Freedom, F. Lecocq, et al, Phys. Rev. Lett. 108, 107001 (2012).
[3] Ultrafast QND measurements based on diamond-shape artificial atom. I. Diniz, et al, Phys. Rev. A 87, 033837 (2013).
报告人简介：
Dr. Olivier Buisson is “Directeur de recherche” at the CNRS. He graduated from Institute National Polytechnic of Grenoble in 1987 and received his PhD from Joseph Fourier University in 1990. After working on plasma modes in superconducting 1D and 2D systems, he initiated in Grenoble the studies on Quantum Superconducting Circuits. Main results have concerned Macroscopic Quantum tunneling in a dc SQUID, multilevel quantum dynamics, tunable coupling between a charge and a phase qubit, Camelback phase qubit.
Current scientific activity includes quantum phase slip in Josephson chains, artificial atoms with two dimensional degrees of freedom, fast QND read out on a phase qubit.
报告邀请人：郑东宁 研究员（8264-9187）