aqora

Strong tunable coupling between a charge qubit and a phase qubit

Aurélien Fay, Emile Hoskinson, Florent Lecocq +4 more

Bulletin of the American Physical SocietyMar 12, 20080 citations

A Tunable Coupling Architecture For Josephson Phase Qubits

Radoslaw C. Bialczak, M. Ansmann, M. Hofheinz +7 more

Bulletin of the American Physical SocietyMar 11, 20080 citations

Strong Tunable Coupling between a Superconducting Charge and Phase Qubit

Aurélien Fay, Emile Hoskinson, Florent Lecocq +4 more

We have realized a tunable coupling over a large frequency range between an asymmetric Cooper pair transistor (charge qubit) and a dc SQUID (phase qubit). Our circuit enables the independent manipulation of the quantum states of each qubit as well as their entanglement. The measurement of the charge qubit's quantum states is performed by an adiabatic quantum transfer from the charge to the phase qubit. The measured coupling strength is in agreement with an analytic theory including a capacitive and a tunable Josephson coupling between the two qubits.We have realized a tunable coupling over a large frequency range between an asymmetric Cooper pair transistor (charge qubit) and a dc SQUID (phase qubit). Our circuit enables the independent manipulation of the quantum states of each qubit as well as their entanglement. The measurement of the charge qubit's quantum states is performed by an adiabatic quantum transfer from the charge to the phase qubit. The measured coupling strength is in agreement with an analytic theory including a capacitive and a tunable Josephson coupling between the two qubits.

arXiv:0712.3970Physical Review LettersMay 6, 200838 citations

Controlled Coupling of Qubits

ScienceNov 30, 20060 citations

Geometric Phase in a Quantum Coherent Tunable Coupling of Superconducting Qubits

元新乔

通过使用Lewis-Riesenfeld不变量理论，我们研究了超导量子位的量子相干可调耦合中的几何相位。发现几何相位与隧道分裂，直流能量偏置和HF信号等无关。这一结果对量子计算有一定的意义。 By using the Lewis-Riesenfeld invariant theory, we have studied the geometric phase in a quantum coherent tunable coupling of superconducting qubits. The geometric phase has nothing to do with the tunnel splitting, but also the dc energy bias and the HF signal. This result has certain significance to the quantum computation.通过使用Lewis-Riesenfeld不变量理论，我们研究了超导量子位的量子相干可调耦合中的几何相位。发现几何相位与隧道分裂，直流能量偏置和HF信号等无关。这一结果对量子计算有一定的意义。 By using the Lewis-Riesenfeld invariant theory, we have studied the geometric phase in a quantum coherent tunable coupling of superconducting qubits. The geometric phase has nothing to do with the tunnel splitting, but also the dc energy bias and the HF signal. This result has certain significance to the quantum computation.

Advances in Condensed Matter PhysicsJan 1, 20180 citations

Tunable-cavity QED with phase qubits

Jed D. Whittaker, F. C. S. da Silva, Michael S. Allman +6 more

We describe a tunable-cavity quantum electrodynamics (QED) architecture with an rf SQUID phase qubit inductively coupled to a single-mode, resonant cavity with a tunable frequency that allows for both microwave readout of tunneling and dispersive measurements of the qubit. Dispersive measurement is well characterized by a three-level model, strongly dependent on qubit anharmonicity, qubit-cavity coupling, and detuning. A tunable-cavity frequency provides a way to strongly vary both the qubit-cavity detuning and coupling strength, which can reduce Purcell losses, cavity-induced dephasing of the qubit, and residual bus coupling for a system with multiple qubits. With our qubit-cavity system, we show that dynamic control over the cavity frequency enables one to avoid Purcell losses during coherent qubit evolutions and optimize state readout during qubit measurements. The maximum qubit decay time ${T}_{1}=1.5\phantom{\rule{0.222222em}{0ex}}\ensuremath{\mu}$s is found to be limited by surface dielectric losses from a design geometry similar to planar transmon qubits.We describe a tunable-cavity quantum electrodynamics (QED) architecture with an rf SQUID phase qubit inductively coupled to a single-mode, resonant cavity with a tunable frequency that allows for both microwave readout of tunneling and dispersive measurements of the qubit. Dispersive measurement is well characterized by a three-level model, strongly dependent on qubit anharmonicity, qubit-cavity coupling, and detuning. A tunable-cavity frequency provides a way to strongly vary both the qubit-cavity detuning and coupling strength, which can reduce Purcell losses, cavity-induced dephasing of the qubit, and residual bus coupling for a system with multiple qubits. With our qubit-cavity system, we show that dynamic control over the cavity frequency enables one to avoid Purcell losses during coherent qubit evolutions and optimize state readout during qubit measurements. The maximum qubit decay time ${T}_{1}=1.5\phantom{\rule{0.222222em}{0ex}}\ensuremath{\mu}$s is found to be limited by surface dielectric losses from a design geometry similar to planar transmon qubits.

arXiv:1408.1760Physical Review BJul 14, 201432 citations

Theory of tunable coupling of phase qubits

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