News: I am joining UC Berkeley as an Assistant Professor in January 2021. Please see the UC Berkeley Quantum Devices Group page for latest updates.
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I am an IQIM postdoctoral scholar in Oskar Painter's group. My interests are broadly in developing new solid-state architectures for applications in quantum information science.
At Caltech, I have been focused on using nanoscale phononic and photonic structures to bring new functionalities to superconducting quantum circuits. We recently developed a wavelength-scale piezoelectric transducer to resonantly couple superconducting qubits and phononic bandgap acoustic resonators with ultralong lifetimes. Using this transducer, we are currently (i) investigating the use of acoustic quantum memories for circuit-QED, (ii) studying microscopic dephasing mechanisms of nano-acoustic resonators at the single-phonon level, and (iii) developing a piezo-optomechanical transducer to create an optical interface for superconducting qubits. |
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Below, you can find some of the highlights of my PhD work in Mikhail Lukin's group at Harvard. A short summary of my PhD thesis is available here.
Research highlights:
Solid-state quantum-emitters with long spin coherence times and strong interactions with single-photons can form the building blocks of a quantum network (see this article for an introduction). In the experiments below, in collaborations with Marko Loncar and Fedor Jelezko's groups, we showed that silicon-vacancy (SiV) color centers in diamond can address both of these challenges.
Solid-state quantum-emitters with long spin coherence times and strong interactions with single-photons can form the building blocks of a quantum network (see this article for an introduction). In the experiments below, in collaborations with Marko Loncar and Fedor Jelezko's groups, we showed that silicon-vacancy (SiV) color centers in diamond can address both of these challenges.
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The silicon-vacancy spin qubit in diamond: 13ms coherence and single-shot state readout DD Sukachev, A Sipahigil, C Nguyen et al. , Phys. Rev. Lett. 119, 223602 (2017) The SiV spin coherence is limited to ~100ns at 4K. In this experiment, we improved the spin coherence time of the SiV by five orders of magnitude to 13ms by operating in a dilution fridge at 100mK. We also demonstrated single-shot optical readout of the SiV spin. Experimentalists curious about operating a free-space confocal microscope in a dilution fridge can find the supplemental material here. An integrated diamond nanophotonics platform for quantum optical networks A Sipahigil, RE Evans, DD Sukachev et al. , Science 10.1126/science.aah6875 (2016) We integrated silicon-vacancy (SiV) color centers into diamond nanophotonic devices to realize quantum nonlinear optical response at the single-photon level and two-SiV entanglement generation. This experiment is the first demonstration of (i) a high-cooperativity spin-photon interface with a color center and (ii) entanglement generation between two solid-state qubits in a single nanophotonic device. The following experiments laid the groundwork for these results: SiV optical properties: Indistinguishable Photons from Separated Silicon-Vacancy Centers in Diamond A Sipahigil, KD Jahnke et al. , Phys. Rev. Lett. 113, 113602 (2014) . We showed that the inversion symmetry of the SiV center suppresses the dephasing of its optical transitions, resulting in narrow inhomogeneous distributions and coherent optical transitions. These results suggested that SiV centers, unlike NV centers, might maintain optical coherence in noisy environments such as nanostructures. (See Physics Viewpoint by Andrew Greentree for a nice perspective on these results) Narrow-Linewidth Homogeneous Optical Emitters in Diamond Nanostructures via Silicon Ion Implantation RE Evans, A Sipahigil, et al. Phys. Rev. Applied 5, 044010 (2016) We found that the SiV optical transitions are spectrally stable inside nanophotonic structures as predicted from their electronic structure. SiV spin properties: All-Optical Initialization, Readout, and Coherent Preparation of Single Silicon-Vacancy Spins in Diamond LJ Rogers, KD Jahnke, et al. Phys. Rev. Lett. 113, 263602 (2014). We showed that the SiV spin states can be optically initialized and read out. (See Physics Viewpoint by Guido Burkard for a nice perspective on these results) Electron–phonon processes of the silicon-vacancy centre in diamond KD Jahnke, A Sipahigil, et al. New Journal of Physics 17, 043011 (2015). We showed that the SiV spin coherence is limited by strong electron-phonon interactions to ~100ns at 4K, and predicted millisecond-scale coherence time at temperatures below 300mK. |