Experimentelle Untersuchung von Kohärenz und Verschränkung in Josephson-Phasenqubits

约瑟夫森相量子位相干性和纠缠性的实验研究

• 批准号: 5414868
• 负责人: Professor Dr. Alexey V. Ustinov, Ph.D.
• 金额: --
• 依托单位: Physikalisches Institut (PHI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5414868?language=en
• 关键词: Experimentelle; Untersuchung; von; Koh; renz

It has been experimentally demonstrated that a variety of micro- and nano-scale superconducting electronic circuits containing Josephson junctions display quantum-coherent dynamics at low temperatures. These circuits are now viewed as very promising candidates to be used as qubits in a future solid state quantum computer. The simplest type of superconduction qubits is the so-called phase qubit, which makes use of the quantum states of a current biased Josephson tunnel junction. These quantum states can be coupled by resonant microwaves to form a controllable two-level systems. We would like to experimentally study individual and coupled Josephson phase qubits. Very recent experiments have shown that these quantum devices can be prepared, controlled and read out by microwave and dc pulses in a manner similar to nuclear spins. Our ultimate goal is to demonstrate coherent manipulation of individual Josephson qubits and create an entanglement between two coupled qubits. In order to achieve this goal, we will study the coupling of Josephson phase qubits to the environment by using tunable interaction between the qubit and on-chip microwave resonators. The relaxation time and the dephasing time of the qubit in the presence of the microwave-tailored environment will be determind. Two Josephsons phase qubits will be coupled capacitively in order to create an entanglement, which will be controlled by dc and microwave pulses. We intend also to study the interaction of the Josephson qubit with the quantized electromagnetic field modes of a high-Q on-chip resonator. We will experimentally characterize the coupling between these two quantum systems and investigate possible mechanisms to create and control their entanglement.

实验证明，各种含有约瑟夫森结的微米级和纳米级超导电子电路在低温下表现出量子相干动力学。这些电路现在被视为非常有希望用作未来固态量子计算机中的量子位的候选电路。最简单的超导量子位类型是所谓的相位量子位，它利用电流偏置约瑟夫森隧道结的量子态。这些量子态可以通过谐振微波耦合形成可控的两能级系统。我们想通过实验研究单个和耦合的约瑟夫森相量子位。最近的实验表明，这些量子器件可以通过微波和直流脉冲以类似于核自旋的方式制备、控制和读出。我们的最终目标是展示单个约瑟夫森量子位的相干操纵，并在两个耦合量子位之间创建纠缠。为了实现这一目标，我们将通过使用量子位和片上微波谐振器之间的可调谐相互作用来研究约瑟夫森相位量子位与环境的耦合。将确定在微波定制环境中量子位的弛豫时间和移相时间。两个约瑟夫森相量子位将电容耦合以产生纠缠，该纠缠将由直流和微波脉冲控制。我们还打算研究约瑟夫森量子位与高 Q 片上谐振器的量化电磁场模式的相互作用。我们将通过实验来表征这两个量子系统之间的耦合，并研究创建和控制它们纠缠的可能机制。