I am an experimental physicist/engineer building new types of quantum devices for applications in computation, communication, and sensing. I am also interested in fundamental studies of quantum coherence in nanoscale devices. Toward these goals, I work with various solid-state platforms, including superconducting circuits, color center spins, and nanoscale optical and acoustic structures.

I am an Assistant Professor at Rice University. Previously, I was an Institute for Quantum Information and Matter (IQIM) postdoctoral scholar in Oskar Painter’s group at Caltech. I received my PhD from Harvard, where I worked in Marko Loncar’s group. I have been fortunate to collaborate with the groups of Liang Jiang (U Chicago), Mikhail Lukin (Harvard), Mete Atature (Cambridge), and Peter Rabl (TU Vienna).

You can reach me by email at srujan[at]rice[dot]edu.



lab-qnd at Rice

I am starting a new research group as an Assistant Professor at Rice University in July 2024. The lab will focus on the physics and engineering of quantum nanoscale devices.

If you are interested in a PhD or postdoc position in experimental quantum science and engineering and would like to discuss research opportunities, please feel free to connect with me.



Research highlights

My work uses chip-scale devices to control interactions between heterogeneous quantum particles. Such hybrid quantum devices that connect physically different qubits will enable new capabilities for next-generation quantum processors and networks. These devices can also serve as powerful tools to probe and engineer the coherence limits of solid-state qubits.

Optical interconnects for superconducting quantum processors

The growing complexity of today’s quantum processors suggests that large-scale quantum computers in the future will likely be modular systems based on a network of processors. To address the quantum interconnect challenge for such networks, I work on transducers that link quantum information in superconducting qubits and optical communication channels.

We recently built such a device and used it to prepare entangled states of single microwave and optical photons for the first time, demonstrating a fundamental requirement for optical networking of superconducting quantum processors. Our device platform integrates superconducting and piezoelectric components with an optomechanical resonator on a silicon chip. When operated at a base temperature of ten millikelvin, a specially engineered acoustic mode in this integrated device allows for entanglement generation between single quanta of light and microwaves.

Quantum entanglement between optical and microwave photonic qubits
Srujan Meesala*, David Lake*, Steven Wood*, Piero Chiappina, Changchun Zhong, Andrew D. Beyer, Matthew D. Shaw, Liang Jiang, Oskar Painter, arXiV:2312.13559 (2023) [PDF]

Non-classical microwave-optical photon pair generation with a chip-scale transducer
Srujan Meesala*, Steven Wood*, David Lake*, Piero Chiappina, Changchun Zhong, Andrew D. Beyer, Matthew D. Shaw, Liang Jiang, Oskar Painter, Nature Physics (2024) [PDF]

Engineering of color-center qubits

Defects in solids can behave like artificial atoms and allow us to encode qubits in their internal electronic levels. Color-center defects can provide optically accessible spin qubits for entanglement distribution over long distances.

We showed that strain control using nanomechanical devices allows for a high degree of engineerability of color-center qubits. For instance, it allowed us to overcome local disorder in the solid-state environment and achieve matched optical and spin transitions on these artificial atoms. We measured a signature of entanglement in photon emission from optically matched emitters in a nanophotonic waveguide and demonstrated an integrated device platform for quantum network nodes.

Quantum interference of electromechanically stabilized emitters in nanophotonic devices
Bartholomeus Machielse*, Stefan Bogdanovic*, Srujan Meesala* et al, Physical Review X 9, 031022 (2019); editor’s choice [PDF]
See focus story in Physics magazine

Strain engineering of the silicon vacancy center in diamond
Srujan Meesala*, Young-Ik Sohn* et al, Physical Review B 97, 205444 (2018); editor’s choice [PDF]

Physics of atomic-scale defects

We used the above devices for spectroscopy of group-IV color centers in diamond and as a controlled experimental platform to study interactions between atomic-scale defects and phonons. We showed the use of strain tuning and acoustic bandgap structures to influence the coherence of a single spin via its phononic environment. This work has intriguing fundamental connections to dielectric loss and decoherence in superconducting quantum circuits.

Controlling the coherence of a diamond spin qubit through its strain environment
Young-Ik Sohn*, Srujan Meesala*, Benjamin Pingault*, et al, Nature Communications 9, 2012 (2018) [PDF]
Featured among 50 most read physics articles of 2018 in the journal; popular summary on Ars Technica

Acceptor-induced bulk dielectric loss in superconducting circuits on silicon
Zi-Huai Zhang, Kadircan Godeneli, Justin He, Mutasem Odeh, Haoxin Zhou, Srujan Meesala, Alp Sipahigil, arXiV:2402.17155 (2024) [PDF]



News

  • 5/29/2024 A scanning electron micrograph of our microwave-optical photon-pair source is featured on the cover of this month’s Nature Physics! [link]

  • 5/29/2024 I will be giving an invited talk in the Nanofabrication for Quantum Computing session at the EIPBN (Three Beams) Conference in San Diego.

  • 3/28/2024 I will be giving a seminar in the ECE Department at the University of Southern California (USC).

  • 3/6/2024 I will be giving a talk at the APS March Meeting in Minneapolis [link].

  • 2/29/2024 I am visiting Boston University and giving a seminar.

  • 2/23/2024 Our work on the non-classical microwave-optical photon-pair source is now published online in Nature Physics! [link]

  • 2/20/2024 I will be visiting Rice University and giving a seminar.

  • 1/31/2024 I will be visiting JILA and giving a colloquium titled ‘Generating quantum correlations between light and microwaves with a chip-scale device’.

  • 12/22/2023 My last paper of this year reports generation of entangled states of photons of light and photons in an electrical circuit. This is the first observation of microwave-optical Bell pairs. Preprint titled ‘Quantum entanglement between optical and microwave photonic qubits’ is now up on the arXiV!

  • 12/04/2023 New preprint titled ‘In-situ tuning of optomechanical crystals with nano-oxidation’ up on the arXiV.

  • 11/17/2023 I am giving the ECE Quantum Seminar at the University of Southern California (USC).

  • 11/14/2023 I have been awarded the Boeing Quantum Creator’s Prize and will be giving a talk at the Chicago Quantum Summit. Many thanks to the Chicago Quantum Exchange and Boeing for this recognition!

  • 10/30/2023 New preprint titled ‘High Q-factor diamond optomechanical resonators with silicon vacancy centers at millikelvin temperatures’ up on the arXiV. These are the first measurements of microwave frequency diamond nanomechanical devices at mK temperatures.

  • 07/25/2023 I am giving an invited seminar in Marko Loncar’s group at Harvard. Excited to visit my old home :).

  • 07/19/2023 I am presenting at the AWS Quantum Networks (QuNeW) Workshop in Beverly MA.

  • 07/07/2023 Our paper titled ‘Design of an ultra-low mode volume piezo-optomechanical quantum transducer’ is now out in Optics Express. This work presents a new design approach for low-noise microwave-optical quantum transducers.

  • 06/29/2023 I am giving an invited seminar in Alp Sipahigil’s group at UC Berkeley.

  • 03/30/2023 New preprint titled ‘Non-classical microwave-optical photon pair generation with a chip-scale transducer’ up on the arXiV. We made the first microwave-optical photon-pair source and observed quantum correlations between light and an electrical circuit. Super excited to put this work out!

  • 03/27/2023 I am giving an invited talk on my recent work on microwave-optical quantum transducers at the AWS Center for Quantum Networks.

  • 03/10/2023 I am giving a talk at the APS March Meeting titled ‘Microwave-optical photon correlations in a piezo-optomechanical transducer’.