Noise Spectroscopy of Superconducting Qubits
-
❑
Noise in superconducting qubits is inevitable! Thus, detection and
investigation of noise spectrum of qubits is necessary to mitigate the
errors originating from the noise. We have implemented newly
developed techniques (by a group from University of Colorado-Boulder)
called Fourier Transform Noise Spectroscopy (FTNS) and Variational
Quantum Noise Spectroscopy (VQNS). And we are the first to
implement these techniques on a superconducting qubit system, in
collaboration with those researchers. -
❑
So far, we have been able to extract the noise spectrum of our single
transmon qubit system using the FTNS protocol on the Ramsey and
Hahn Echo datasets, upto a certain frequency range (~ 100 MHz)
limited by our measurement equipment’s resolution. -
❑
Further, using VQNS protocol, we were able to predict the noise
spectrum at frequencies (~ 1GHz) beyond the above range.
Upcoming Work
-
•
Design of filters in the suitable frequency range to be
implemented physically in the cryogenic lines for noise elimination. -
•
Design of proper pulse shapes using various filter techniques -
•
Apply FTNS and VQNS to find noise due to inter-qubit cross-talk
in our current 5-qubit system.