Calendar:
Physics 838 Seminar
Date:
05.01.2017 4:00 pm - 5:00 pm
Location:

Description

SPEAKER: Ziyuan Fu
Advisor: S. Anlage


============================================
SPEAKER: Long NGuyen
Advisor: V. Manucharyan

TITLE: Protecting a multi-level superconducting artificial atom from energy relaxation.

ABSTRACT: The inter-well "fluxon" transition of a fluxonium circuit has a dipole matrix element that decreases drastically as the ratio EJ/EC becomes large due to a weak overlap of wavefunctions localized in the two Josephson wells. Thus naturally suppresses all linear energy relaxation mechanisms, such as dielectric loss. Despite the vanishing transition dipole of such a qubit, there is still a finite dispersive shift due to the presence of strongly-coupled intra-well "plasmon" transitions in the circuit. By tuning EJ/EC ratio with an external magnetic flux we observed a factor of 100 enhancement of qubit lifetime from about 20 microseconds to over 2 millisecond for a nearly the same transition frequency. T2 measurement is performed both at the spots maximally-sensitive to flux noise - where it never drops below a microsecond - and at the flux sweet spot where it is over 150us. Our experiment demonstrates that a highly-decoupled, long-lived qubit can still be coherently manipulated and read out in a multi-level superconducting circuit.

Upcoming Events

May
1

05.01.2017 4:00 pm - 5:00 pm

May
4

05.04.2017 2:00 pm - 3:30 pm

May
8

05.08.2017 4:00 pm - 5:00 pm

May
11

05.11.2017 2:00 pm - 3:30 pm

Sep
4

09.04.2017 4:00 pm - 5:00 pm