You are welcome to join the Quantum seminar next week.
"Coupled modes in nonlinear superconducting circuits for device characterization and generation of correlated photons"
Nonlinear low-loss superconducting circuits are leading candidates for
implementation of quantum information processing, quantum simulation and for
low-noise amplification. Careful characterization of their loss properties and
nonlinearity is needed in order to aid the design of the devices. In this work we show
that coupled modes can be used to improve the characterization of superconducting
devices and reveal their nonlinear properties. In addition, we show that their
nonlinear kinetic inductance (KI) can result in mode coupling through three-wave
mixing which can be used for broadband generation of two-mode correlated
photons and amplification. I will present three projects:
I. We use the normal modes of two coupled Al resonators to reveal the full
nonlinearity of loss-inducing tunneling two-level systems in the
device’s dielectric .
II. We exploit the cross mode coupling in a multimode tungsten-silicide (WSi)
resonator to characterize the Kerr-type KI nonlinearity which is hidden by
other spurious nonlinearities when a single-mode characterization is used .
III. We use the nonlinear KI of a WSi traveling wave parametric amplifier 
to generate broadband two-mode correlated photons and demonstrate both phase
sensitive and phase insensitive amplification using three-wave mixing.
 Kirsh, N., Svetitsky, E., Burin, A. L., Schechter, M., & Katz, N. (2017). Revealing the nonlinear response of a tunneling two-level system ensemble using coupled modes. Physical Review Materials, 1(1), 012601.
 Kirsh, N., Svetitsky, E., Goldstein, S., Pardo, G., Hachmo, O., & Katz, N. (2021). Linear and nonlinear properties of a compact high-kinetic-inductance WSi multimode resonator. Physical Review Applied, 16(4), 044017.
 Goldstein, S., Kirsh, N., Svetitsky, E., Zamir, Y., Hachmo, O., de Oliveira, C. E. M., & Katz, N. (2020). Four wave-mixing in a microstrip kinetic inductance travelling wave parametric amplifier. Applied Physics Letters, 116(15), 152602.