Current Science

Open Access Open Access  Restricted Access Subscription Access

Quantum Measurements with Superconducting Circuits


Affiliations
1 Quantum Measurement and Control Laboratory, Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400 005, India
2 Quantum Measurement and Control Laboratory, Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400 005, India
 

We measure the state of a superconducting quantum bit (qubit) coupled to a microwave cavity by scattering a microwave signal from the cavity. The scattered signal is amplified using a low-noise Josephson parametric amplifier. We carried out measurements to infer the coherence properties of the qubit. In the strong measurement regime, we observe quantum jumps between the qubit states in real time, while we observe stochastic quantum trajectories in the weak measurement regime. The coherence times and measurement fidelity obtained are sufficient for implementing quantum error correction.

Keywords

Circuit QED, Coherence Properties, Qubits, Quantum Measurement, Superconducting Circuits.
User
Notifications
Font Size

  • Nielsen, M. and Chuang, I., Quantum Computation and Quantum Information, Cambridge University Press, 2000.

  • Braginsky, V. B. and Khalili, F. Ya., Quantum nondemolition measurements: the route from toys to tools. Rev. Mod. Phys., 1996, 68(1), 1–11.

  • Gardiner, C. and Zoller, P., Quantum Noise, Springer, 2004.

  • Goan, H.-S., Milburn, G. J., Wiseman, H. M. and Sun, H. B., Continuous quantum measurement of two coupled quantum dots using a point contact: a quantum trajectory approach. Phys. Rev. B, 2001, 63(12), 125326-1 to 12.

  • Korotkov, A. N., Continuous quantum measurement of a double dot. Phys. Rev. B, 1999, 60(8) 5737–5742.

  • Devoret, M. H. and Schoelkopf, R. J., Superconducting circuits for quantum information: an outlook. Science, 2013, 339(6124), 1169–1174.

  • You, J. Q. and Nori, F., Atomic physics and quantum optics using superconducting circuits. Nature, 2011, 474(7353), 589–597.

  • Blais, A., Huang, R.-S., Wallraff, A., Girvin, S. M. and Schoelkopf, R. J., Cavity quantum electrodynamics for superconducting electrical circuits: an architecture for quantum computation. Phys. Rev. A, 2004, 69(6), 062320-1 to 14.

  • Wallraff, A. et al., Strong coupling of a single photon to a superconducting qubit using circuit quantum electrodynamics. Nature, 2004, 431(7005), 162–167.

  • Castellanos-Beltran, M. A., Irwin, K. D., Hilton, G. C., Vale, L. R. and Lehnert., K. W., Amplification and squeezing of quantum noise with a tunable Josephson metamaterial. Nature Phys., 2008, 4(12), 929–931.

  • Hatridge, M., Vijay, R., Slichter, D. H., Clarke, J. and Siddiqi, I., Dispersive magnetometry with a quantum limited SQUID parametric amplifier. Phys. Rev. B, 2011, 83(13), 134501-1 to 8.

  • Josephson, B. D., Coupled superconductors. Rev. Mod. Phys., 1964, 36(1), 216–220.

  • Koch, J. et al., Charge-insensitive qubit design derived from the Cooper pair box. Phys. Rev. A, 2007, 76(4), 042319-1 to 19.

  • Kelly, J. et al., State preservation by repetitive error detection in a superconducting quantum circuit. Nature, 2015, 519(7541), 66–69.

  • Córcoles, A. D., Magesan, E., Srinivasan, S. J., Cross, A. W., Steffen, M., Gambetta, J. M. and Chow, J. M., Demonstration of a quantum error detection code using a square lattice of four superconducting qubits. Nature Commun., 2015, 6, 6979-1 to 10.

  • Berman, P. (ed.), Cavity Quantum Electrodynamics, Academic Press, 1994.

  • Paik, H. et al., Observation of high coherence in Josephson junction qubits measured in a three-dimensional circuit QED architecture. Phys. Rev. Lett., 2011, 107(24), 240501-1 to 5.

  • Houck, A. A. et al., Controlling the spontaneous emission of a superconducting transmon qubit. Phys. Rev. Lett., 2008, 101(8), 080502-1 to 4.

  • Korotkov, A. N., Quantum Bayesian approach to circuit QED measurement. arXiv:1111.4016[quant-ph].

  • Hatridge, M. et al., Quantum back-action of an individual variablestrength measurement. Science, 2013, 339(6116), 178-181.

  • Murch, K. W., Weber, S. J., Macklin, C. and Siddiqi, I., Observing single quantum trajectories of a superconducting qubit. Nature, 2013, 502(7470), 211–214.

  • Vijay, R., Slichter, D. H. and Siddiqi, I., Observation of quantum jumps in a superconducting artificial atom. Phys. Rev. Lett., 2011, 106(11), 110502-1 to 4.

  • Vijay, R. et al., Stabilizing Rabi oscillations in a superconducting qubit using quantum feedback. Nature, 2012, 490(7418), 77–80.

  • Weber, S. J., Chantasri, A., Dressel, J., Jordan, A. N., Murch, K. W. and Siddiqi, I., Mapping the optimal route between two quantum states. Nature, 2014, 511(7511), 570–573.

  • Collin, E., Ithier, G., Aassime, A., Joyez, P., Vion, D. and Esteve, D., NMR-like control of a quantum bit superconducting circuit. Phys. Rev. Lett., 2004, 93(15), 157005-1 to 4.

  • Ithier, G. et al., Decoherence in a superconducting quantum bit circuit. Phys. Rev. B, 2005, 72(13), 134519-1 to 22.

  • Terhal, B. M., Quantum error correction for quantum memories. Rev. Mod. Phys., 2015, 87(2), 307–346.

  • Fedorov, A., Steffen, L., Baur, M., Da Silva, M. P. and Wallraff, A., Implementation of a Toffoli gate with superconducting circuits. Nature, 2011, 481(7380), 170-172.

  • Reed, M. D., DiCarlo, L., Nigg, S. E., Sun, L., Frunzio, L., Girvin, S. M. and Schoelkopf, R. J., Realization of three-qubit quantum error correction with superconducting circuits. Nature, 2012, 482(7385), 382–385.

  • Ristè, D., Poletto, S., Huang, M.-Z., Bruno, A., Vesterinen, V., Saira, O.-P. and DiCarlo, L., Detecting bit-flip errors in a logical qubit using stabilizer measurements. Nature Commun., 2015, 6, 6983-1 to 6.


Abstract Views: 266

PDF Views: 98




  • Quantum Measurements with Superconducting Circuits

Abstract Views: 266  |  PDF Views: 98

Authors

Tanay Roy
Quantum Measurement and Control Laboratory, Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400 005, India
A. M. Vadiraj
Quantum Measurement and Control Laboratory, Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400 005, India
Madhavi Chand
Quantum Measurement and Control Laboratory, Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400 005, India
A. Ranadive
Quantum Measurement and Control Laboratory, Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400 005, India
Suman Kundu
Quantum Measurement and Control Laboratory, Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400 005, India
Meghan P. Patankar
Quantum Measurement and Control Laboratory, Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400 005, India
R. Vijay
Quantum Measurement and Control Laboratory, Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400 005, India

Abstract


We measure the state of a superconducting quantum bit (qubit) coupled to a microwave cavity by scattering a microwave signal from the cavity. The scattered signal is amplified using a low-noise Josephson parametric amplifier. We carried out measurements to infer the coherence properties of the qubit. In the strong measurement regime, we observe quantum jumps between the qubit states in real time, while we observe stochastic quantum trajectories in the weak measurement regime. The coherence times and measurement fidelity obtained are sufficient for implementing quantum error correction.

Keywords


Circuit QED, Coherence Properties, Qubits, Quantum Measurement, Superconducting Circuits.

References





DOI: https://doi.org/10.18520/cs%2Fv109%2Fi11%2F2069-2076