Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session Y34: CV Quantum Computation and Simulation III
8:00 AM–11:00 AM,
Friday, March 18, 2022
Room: McCormick Place W-193A
Sponsoring Unit: DQI
Chair: Ruoming Peng, University of Chicago
Abstract: Y34.00006 : Pairwise exponential level kissing in the Kerr-cat eigenspectrum (part 1/2)*
9:24 AM–9:36 AM
Rodrigo G Cortiñas
Rodrigo G Cortiñas
Nicholas E Frattini
Chan U Lei
Vidul R Joshi
Benjamin J Chapman
Steven M Girvin
Michel H Devoret
Schrödinger cat states, superpositions of coherent states in an oscillator, can be stabilized by a driven effective Hamiltonian thanks to the interplay between Kerr nonlinearity and single-mode squeezing.
The pair of resulting degenerate Kerr-cat states form a qubit whose coherence along one Bloch sphere axis is increasing exponentially with the average photon number, while decreasing only linearly along the other axes.
The qubit protection arises from the progressive pairwise kissing of consecutive levels as the average photon number is increased--a quantum manifestation of robust period doubling in this system.
We experimentally observe the pairwise kissing via spectroscopy, and the associated increase in the period-doubled coherent state lifetime, which reaches 1 ms, a factor of 480 improvement over the bare lifetime of the constituent SNAIL-transmon circuit.
In the first part of this two-part presentation, we review the explored Hamiltonian system and its high-fidelity, nondemolition measurement.
In the second part of this two-part presentation, we discuss the spectroscopy and the lifetime scaling for the coherent states and their superpositions in our system.
*ARO, NSF, and YINQE
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