About

Srivatsan Chakram is an Assistant Professor and a member of the Graduate Faculty in the Department of Physics and Astronomy at Rutgers University. His group's research is at the intersection of quantum information science, quantum optics, and condensed matter physics. They focus on building devices that combine superconducting circuits and microwave cavities with extremely low losses to explore their quantum properties at millikelvin temperatures. The microwave cavities used are typically multimodal, possessing tens of modes with photon lifetimes of a few milliseconds, forming multimode cavity QED systems with extremely high cooperativities when combined with superconducting circuits. His research involves developing new quantum processors and memories, exploring schemes for quantum control and quantum error correction in these systems. The work also aims to explore a new regime of many-body quantum optics and the potential for building exotic quantum materials using microwave light. His contributions advance the understanding and development of quantum technologies, with a focus on quantum information processing and quantum optics.

Research topics

• Physics
• Quantum mechanics
• Quantum electrodynamics
• Particle physics

Selected publications

• Chiral cavity quantum electrodynamics

  Nature Physics · 2022 · 84 citations

  • Physics
  • Quantum mechanics
  • Quantum electrodynamics
  PublisherDOI

• Searching for Dark Matter with a Superconducting Qubit

  Physical Review Letters · 2021 · 177 citations

  • Physics
  • Particle physics
  • Quantum mechanics

  Detection mechanisms for low mass bosonic dark matter candidates, such as the axion or hidden photon, leverage potential interactions with electromagnetic fields, whereby the dark matter (of unknown mass) on rare occasion converts into a single photon. Current dark matter searches operating at microwave frequencies use a resonant cavity to coherently accumulate the field sourced by the dark matter and a near standard quantum limited (SQL) linear amplifier to read out the cavity signal. To further increase sensitivity to the dark matter signal, sub-SQL detection techniques are required. Here we report the development of a novel microwave photon counting technique and a new exclusion limit on hidden photon dark matter. We operate a superconducting qubit to make repeated quantum nondemolition measurements of cavity photons and apply a hidden Markov model analysis to reduce the noise to 15.7 dB below the quantum limit, with overall detector performance limited by a residual background of real photons. With the present device, we perform a hidden photon search and constrain the kinetic mixing angle to ε≤1.68×10^{-15} in a band around 6.011 GHz (24.86 μeV) with an integration time of 8.33 s. This demonstrated noise reduction technique enables future dark matter searches to be sped up by a factor of 1,300. By coupling a qubit to an arbitrary quantum sensor, more general sub-SQL metrology is possible with the techniques presented in this Letter.

  DOI

Frequent coauthors

• David Schuster

  Electronics for Imaging (United States)

  50 shared

• Ravi Naik

  39 shared

• Mukund Vengalattore

  Defense Advanced Research Projects Agency

  28 shared

• Nelson L. C. Leung

  Hong Kong University of Science and Technology

  25 shared

• Yogesh Sharad Patil

  Yale University

  22 shared

• Akash Dixit

  University of Chicago

  22 shared

• Yao Lu

  21 shared

• Jens Koch

  20 shared

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