Enhanced coherence in superconducting circuits via band engineering

• URL: http://arxiv.org/abs/2012.11884v1
• Date: Tue, 22 Dec 2020 09:01:45 GMT
• Title: Enhanced coherence in superconducting circuits via band engineering
• Authors: Luca Chirolli and Joel E. Moore
• Abstract summary: In superconducting circuits interrupted by Josephson junctions, the dependence of the energy spectrum on offset charges on different islands is $2e$ periodic. We show that higher-harmonic Josephson elements described by a $cos(2varphi)$ energy-phase relation provide an increased freedom to tailor the shape of the Josephson potential.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: In superconducting circuits interrupted by Josephson junctions, the dependence of the energy spectrum on offset charges on different islands is $2e$ periodic through the Aharonov-Casher effect and resembles a crystal band structure that reflects the symmetries of the Josephson potential. We show that higher-harmonic Josephson elements described by a $\cos(2\varphi)$ energy-phase relation provide an increased freedom to tailor the shape of the Josephson potential and design spectra featuring multiplets of flat bands and Dirac points in the charge Brillouin zone. Flat bands provide noise-insensitive quantum states, and band engineering can help improve the coherence of the system. We discuss a modified version of a flux qubit that achieves in principle no decoherence from charge noise and introduce a flux qutrit that shows a spin-one Dirac spectrum and is simultaneously quote robust to both charge and flux noise.

Related papers

• Josephson bifurcation readout: beyond the monochromatic approximation [49.1574468325115]
  We analyze properties of bifurcation quantum detectors based on weakly nonlinear superconducting resonance circuits. This circuit can serve as an efficient detector of the quantum state of superconducting qubits.
  arXiv  Detail & Related papers  (2024-05-25T22:22:37Z)
• Tunneling of fluxons via a Josephson resonant level [0.0]
  A superconducting loop can be coherently coupled by quantum phase slips occurring at a weak link such as a Josephson junction. We analyze this scenario by computing the coupling between fluxons as the level is brought into resonance with the superconducting condensate. These findings can inform experiments on bifluxon qubits as well as the design of novel types of protected qubits.
  arXiv  Detail & Related papers  (2023-10-04T18:33:30Z)
• Dissipative stabilization of maximal entanglement between non-identical emitters via two-photon excitation [49.1574468325115]
  Two non-identical quantum emitters, when placed within a cavity and coherently excited at the two-photon resonance, can reach stationary states of nearly maximal entanglement. We show that this mechanism is merely one among a complex family of phenomena that can generate both stationary and metastable entanglement when driving the emitters at the two-photon resonance.
  arXiv  Detail & Related papers  (2023-06-09T16:49:55Z)
• Observation of Josephson Harmonics in Tunnel Junctions [0.9263754304004778]
  State-of-the-art technologies, including the world's largest quantum processors, employ aluminum oxide (AlO$_x$) tunnel Josephson junctions (JJs) as sources of nonlinearity. Here we show that the standard C$varphi$R fails to accurately describe the energy spectra of transmon artificial atoms. By including these in the transmon Hamiltonian, we obtain orders of magnitude better agreement between the computed and measured energy spectra.
  arXiv  Detail & Related papers  (2023-02-17T23:52:55Z)
• The Josephson junction as a quantum engine [44.56439370306859]
  Cooper pairs in superconducting electrodes of a Josephson junction (JJ) as an open system, coupled via Andreev scattering to external baths of electrons. Disequilibrium between the baths generates the direct-current bias applied to the JJ. We argue that this picture of the JJ as a quantum engine resolves open questions about the Josephson effect as an irreversible process and could open new perspectives in quantum thermodynamics and in the theory of dynamical systems.
  arXiv  Detail & Related papers  (2023-02-09T16:51:39Z)
• Directional Josephson traveling-wave parametric amplifier via non-Hermitian topology [58.720142291102135]
  Low-noise microwave amplification is crucial for detecting weak signals in quantum technologies and radio astronomy. Current amplifiers do not satisfy all these requirements, severely limiting the scalability of superconducting quantum devices. Here, we demonstrate the feasibility of building a near-ideal quantum amplifier using a homogeneous Josephson junction array and the non-trivial topology of its dynamics.
  arXiv  Detail & Related papers  (2022-07-27T18:07:20Z)
• Driving Force and Nonequilibrium Vibronic Dynamics in Charge Separation of Strongly Bound Electron-Hole Pairs [59.94347858883343]
  We study the dynamics of charge separation in one, two and three-dimensional donor-acceptor networks. This allows us to identify the precise conditions in which underdamped vibrational motion induces efficient long-range charge separation.
  arXiv  Detail & Related papers  (2022-05-11T17:51:21Z)
• Evidence of Josephson coupling in a few-layer black phosphorus planar Josephson junction [45.82374977939355]
  We show evidence of Josephson coupling in a planar few-layer black Phosphorus junction. Clear signatures of Josephson coupling are demonstrated by measuring supercurrent flow through the junction at milli Kelvin temperatures. These findings represent the first evidence of proximity Josephson coupling in a planar junction based on a van der Waals material beyond graphene.
  arXiv  Detail & Related papers  (2021-10-06T16:06:58Z)
• Level attraction and idler resonance in a strongly driven Josephson cavity [0.0]
  Josephson circuits play a crucial role in the growing landscape of quantum information and technologies. Small anharmonicity but also narrow linewidth has not been extensively explored using Josephson cavities. We use two-tone spectroscopy to study the susceptibility of a strongly driven high-$Q$ Josephson microwave cavity.
  arXiv  Detail & Related papers  (2021-09-03T09:45:43Z)
• dc to ac Josephson transition in a dc atom superconducting quantum interference device [0.0]
  We analyze the effect of the barrier motion on the Bose-Hubbard Hamiltonian of a ring-shaped Bose-Einstein condensate interrupted by a pair of Josephson junctions. Such an effect is also shown to modify the Heisenberg equation of motion of the boson field operator.
  arXiv  Detail & Related papers  (2020-08-02T17:34:11Z)
• Landau-Zener-St\"uckelberg Interferometry in dissipative Circuit Quantum Electrodynamics [0.0]
  We study Landau-Zener-St"uckelberg (LZS) interferometry in a cQED architecture under effects of dissipation. We unveil important differences in the resonant patterns between the Strong Coupling and Ultra Strong Coupling regimes in the qubit-resonator interaction.
  arXiv  Detail & Related papers  (2020-02-25T12:38:35Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.