Michael Hatridge

Josephson directional amplifier for quantum measurement of superconducting circuits

  1. Baleegh Abdo,
  2. Katrina Sliwa,
  3. S. Shankar,
  4. Michael Hatridge,
  5. Luigi Frunzio,
  6. Robert Schoelkopf,
  7. and Michel Devoret
We have realized a microwave quantum-limited amplifier that is directional and can therefore function without the front circulator needed in many quantum measurements. The amplification
takes place in only one direction between the input and output ports. Directionality is achieved by multi-pump parametric amplification combined with wave interference. We have verified the device noise performances by using it to readout a superconducting qubit and observed quantum jumps. With an improved version of this device, qubit and preamplifer could be integrated on the same chip.
arxiv pdf

Full coherent frequency conversion between two microwave propagating modes

  1. Baleegh Abdo,
  2. Katrina Sliwa,
  3. Flavius Schackert,
  4. Nicolas Bergeal,
  5. Michael Hatridge,
  6. Luigi Frunzio,
  7. A. Douglas Stone,
  8. and Michel H. Devoret
We demonstrate full frequency conversion in the microwave domain using a Josephson three-wave mixing device pumped at the difference between the frequencies of its fundamental eigenmodes.
By measuring the signal output as a function of the intensity and phase of the three input signal, idler and pump tones, we show that the device functions as a controllable three-wave beam-splitter/combiner for propagating microwave modes, in accordance with theory. Losses at the full conversion point are found to be less than 10^-2. Potential applications of the device include quantum information transduction and realization of an ultra-sensitive interferometer with controllable feedback.
arxiv pdf