Abstract
Dielectric loss from two-level states is shown to be a dominant decoherence source in superconducting quantum bits. Depending on the qubit design, dielectric loss from insulating materials or the tunnel junction can lead to short coherence times. We show that a variety of microwave and qubit measurements are well modeled by loss from resonant absorption of two-level defects. Our results demonstrate that this loss can be significantly reduced by using better dielectrics and fabricating junctions of small area 10μm2. With a redesigned phase qubit employing low-loss dielectrics, the energy relaxation rate has been improved by a factor of 20, opening up the possibility of multiqubit gates and algorithms.
Original language | English (US) |
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Article number | 210503 |
Journal | Physical review letters |
Volume | 95 |
Issue number | 21 |
DOIs | |
State | Published - Nov 18 2005 |
All Science Journal Classification (ASJC) codes
- General Physics and Astronomy