Coherent Quantum Dynamics of a Superconducting Flux Qubit

By I. Chiorescu, Yasunobu Nakamura, C. Harmans, J. Mooij. Science, 2003

1,036 citations recorded by the source corpus.

We have observed coherent time evolution between two quantum states of a superconducting flux qubit comprising three Josephson junctions in a loop. The superposition of the two states carrying opposite macroscopic persistent currents is manipulated by resonant microwave pulses. Readout by means of switching-event measurement with an attached superconducting quantum interference device revealed quantum-state oscillations with high fidelity. Under strong microwave driving, it was possible to induce hundreds of coherent oscillations. Pulsed operations on this first sample yielded a relaxation time of 900 nanoseconds and a free-induction dephasing time of 20 nanoseconds. These results are promising for future solid-state quantum computing.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/29c4f9a52420e3594beb4161f26af9ee2ad0df63

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In Atomic and Molecular Physics, and Optics

Citations in the corpus

Breakdown of gauge invariance in ultrastrong-coupling cavity QED (2018, background): “For this plot, the values for EJ , ELq , and ECq have been chosen such that the frequency ω10 ≈ 3 GHz and nonlinearity parameter nl ≈ 15 are consistent with actual experimental values [90].”
Fault-tolerant computing with biased-noise superconducting qubits: a case study (2008, background): “Since the initial demonstration of coherent quantum dynamics in superconducting qubits [2]–[5], it has been recognized that these systems have great potential versatility [6]–[8], so that one can genuinely envision a quantum-computing integrated circuit emerging from this research.”
Coherent coupling of a superconducting flux qubit to an electron spin ensemble in diamond (2011, background): “The degeneracy point is optimal because at this point the qubit is decoupled from low frequency flux noise and has maximum coherence time [3, 4].”
Qudits and High-Dimensional Quantum Computing (2020, methodology): “For many of the physical systems such as photons [113, 132]; super conducting systems [29, 31]; trapped ions [14, 15]; magnetic [7, 18, 32, 148] and non-magnetic molecules [30, 152] there are usually more than two available physical states available for the applications.”
Do We Really Understand Quantum Mechanics? (2012, background): “Another interesting quantum system is provided by a coherent superposition of opposite persistent currents in a SQUID [364]; further studies have shown that the decoherence process can be mastered and studied precisely [365].”
Introduction to quantum electromagnetic circuits (2016, methodology): “The flux qubit [43] is derived from the original proposal by Leggett of observing macroscopic quantum coherence oscillations between flux states of the radio frequency (RF)Superconducting Quantum Interference Device (SQUID).”
Superconducting nanocircuits for topologically protected qubits (2008, background): “The existence of such a “sweet spot” in the qubit parameters space, where the qubit is decoupled from noise in linear order, has been already established for superconducting qubits [7,8,9,10].”
Circuit QED: Superconducting Qubits Coupled to Microwave Photons (2015, background): “, 2008) based on charge, the flux qubit (Mooij et al., 1999; van der Wal et al., 2000; Chiorescu et al., 2003), and the phase qubit (Martinis et al.”