Session Z29: Focus Session: Superconducting Qubits: Noise and Anomalous Temperature

11:15 AM–1:27 PM, Friday, March 2, 2012
Room: 259A

Sponsoring Unit: GQI
Chair: Will Oliver, MIT/ Lincoln Laboratory

Abstract ID: BAPS.2012.MAR.Z29.11

Abstract: Z29.00011 : Designs towards improved coherence times in superconducting qubits

1:15 PM–1:27 PM

Preview Abstract MathJax On | Off     Abstract  

Authors:

  Antonio Corcoles
    (IBM TJ Watson Research Center)

  Jerry Chow
    (IBM TJ Watson Research Center)

  Jay Gambetta
    (IBM TJ Watson Research Center)

  Chad Rigetti
    (IBM TJ Watson Research Center)

  Jim Rozen
    (IBM TJ Watson Research Center)

  George Keefe
    (IBM TJ Watson Research Center)

  Mary Beth Rothwell
    (IBM TJ Watson Research Center)

  Stefano Poletto
    (IBM TJ Watson Research Center)

  Mark Ketchen
    (IBM TJ Watson Research Center)

  Matthias Steffen
    (IBM TJ Watson Research Center)

Coherence times for superconducting qubits in a planar geometry have increased drastically over the past 10 years with improvements exceeding a factor of 1000. However, recently these appeared to have reached a plateau around 1-2 microseconds, the limits of which were not well understood. Here, we present experimental data showing that one limit is due to infra-red radiation, confirming observations from other groups. We observe increased coherence times after appropriate IR shielding. Further improvements are shown to be possible by increasing the feature size of the interdigitated shunting capacitor, strongly indicating that surface losses at the metal/substrate interface are limiting qubit coherence times. In our experiments we kept the ratio of line width to gap size constant, but increased the overall feature size. We will discuss this and other similar design approaches towards better coherence in superconducting qubits.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2012.MAR.Z29.11