Professor, Northwestern University; Devices Focus Area Team Member, SQMS
Areas of Expertise: Quantum Devices, Quantum Communication, Quantum Optics, Quantum Sensing
Thrust: Technology, Science
Prem Kumar works on quantum measurement tools to support the development of quantum materials, devices, prototypes, and testbeds for systems based on superconducting technologies. Kumar Lab at Northwestern has a long history of developing quantum measurement tools for characterizing continuous-variable (CV) and discrete-variable (DV) quantum signals. These include the standard single-mode measurements: direct detection (photon counting), homodyne detection, heterodyne detection, and up-conversion detection (mode-resolved photon counting) with homodyne (CV) and qubit (DV) tomographies for characterizing the single-mode quantum states; and multimode measurements, both CV and DV, for characterizing entanglement between the various quantum modes: photon correlation measurements, quadrature correlation measurements, multimode quantum state and process tomographies (both homodyne for CV and qubit for DV), and entanglement characterization with the latest compressed sensing and machine learning tools. Although the focus of work at Kumar Lab has been in the optical domain (mostly telecom band), SQMS is extending that work to develop similar measurement tools for characterizing microwave quantum signals. The physics is the same, photonic wavelength being the only difference, which means that a different set of hardware is required. For example, using Josephson junction parametric devices, they plan to implement microwave quantum tools paralleling their legacy and ongoing work in the optical domain.