6 papers
Low-energy spectrum of double-junction superconducting circuits in the Born-Oppenheimer approximation
Leo Uhre Jakobsen, Ksenia Shagalov, David Feldstein-Bofill +3
The superconductor-insulator-superconductor Josephson junction is the fundamental nonlinear element of superconducting circuits. Connecting two junctions in series gives rise to hi…
Observation of coherent flux-charge interaction in a gate-tunable fluxonium
Brian D. Isakov, Shikhar Singh, Adrian Parra-Rodriguez +7
Interactions that mix conjugate variables, such as the flux through a circuit element and the charge across it, lie outside the reach of the elementary couplings of superconducting…
Junction-Intrinsic Dissipation in Hybrid Superconductor-Semiconductor Gatemon Qubits
Zhenhai Sun, David Feldstein-Bofill, Ksenia Shagalov +10
Superconducting transmon qubits based on hybrid superconductor-semiconductor Josephson junctions (gatemons) offer gate tunability, but their relaxation times remain well below thos…
Controlled Parity of Cooper Pair Tunneling in a Hybrid Superconducting Qubit
David Feldstein-Bofill, Leo Uhre Jacobsen, Ksenia Shagalov +9
Superconducting quantum circuits derive their nonlinearity from the Josephson energy-phase relation. Besides the fundamental term, this relation can also contain higher Fo…
Higher Josephson harmonics in a tunable double-junction transmon qubit
Ksenia Shagalov, David Feldstein-Bofill, Leo Uhre Jakobsen +11
Tunable Josephson harmonics open new avenues for qubit design. We demonstrate a superconducting circuit element consisting of a tunnel junction in series with a SQUID loop, yieldin…
Gatemon Qubit Revisited for Improved Reliability and Stability
David Feldstein-Bofill, Zhenhai Sun, Casper Wied +6
The development of quantum circuits based on hybrid superconductor-semiconductor Josephson junctions holds promise for exploring their mesoscopic physics and for building novel sup…