Confining the state of light to a quantum manifold by engineered two-photon loss

A way to induce quantum stability Dynamical systems, whether classical or quantum, usually require a method to stabilize performance and maintain the required state. For instance, communication between computers requires error correction codes to ensure that information is transferred correctly. In a quantum system, however, the very act of measuring it can perturb it. Leghtas et al. show that engineering the interaction between a quantum system and its environment can induce stability for the delicate quantum states, a process that could simplify quantum information processing. Science, this issue p. 853 Controlling the dynamics of a quantum system can provide a route to stabilization. Physical systems usually exhibit quantum behavior, such as superpositions and entanglement, only when they are sufficiently decoupled from a lossy environment. Paradoxically, a specially engineered interaction with the environment can become a resource for the generation and protection of quantum states. This notion can be generalized to the confinement of a system into a manifold of quantum states, consisting of all coherent superpositions of multiple stable steady states. We have confined the state of a superconducting resonator to the quantum manifold spanned by two coherent states of opposite phases and have observed a Schrödinger cat state spontaneously squeeze out of vacuum before decaying into a classical mixture. This experiment points toward robustly encoding quantum information in multidimensional steady-state manifolds.

[1]  Erik Lucero,et al.  Synthesizing arbitrary quantum states in a superconducting resonator , 2009, Nature.

[2]  S. Girvin,et al.  Observation of quantum state collapse and revival due to the single-photon Kerr effect , 2012, Nature.

[3]  H. Carmichael.  Statistical Methods in Quantum Optics 2 , 2008 .

[4]  R. J. Schoelkopf,et al.  Phase-preserving amplification near the quantum limit with a Josephson ring modulator , 2009, Nature.

[5]  S. Deleglise,et al.  Reconstruction of non-classical cavity field states with snapshots of their decoherence , 2008, Nature.

[6]  J. Dowling.  Exploring the Quantum: Atoms, Cavities, and Photons. , 2014 .

[7]  R. Bowler,et al.  Dissipative production of a maximally entangled steady state of two quantum bits , 2013, Nature.

[8]  Christine A Muschik,et al.  Entanglement generated by dissipation and steady state entanglement of two macroscopic objects. , 2010, Physical review letters.

[9]  R. J. Schoelkopf,et al.  Resolving photon number states in a superconducting circuit , 2007, Nature.

[10]  R. J. Schoelkopf,et al.  Reaching 10 ms single photon lifetimes for superconducting aluminum cavities , 2013, 1302.4408.

[11]  S. Girvin,et al.  Photon Shot Noise Dephasing in the Strong-Dispersive Limit of Circuit QED , 2012, 1206.1265.

[12]  J. Teufel,et al.  Sideband cooling of micromechanical motion to the quantum ground state , 2011, Nature.

[13]  S. Girvin,et al.  Deterministically Encoding Quantum Information Using 100-Photon Schrödinger Cat States , 2013, Science.

[14]  Mazyar Mirrahimi,et al.  Persistent control of a superconducting qubit by stroboscopic measurement feedback , 2012, 1301.6095.

[15]  Mazyar Mirrahimi,et al.  Real-time quantum feedback prepares and stabilizes photon number states , 2011, Nature.

[16]  S. Girvin,et al.  Quantum non-demolition detection of single microwave photons in a circuit , 2010, 1003.2734.

[17]  Carmichael,et al.  Quantum noise in the parametric oscillator: From squeezed states to coherent-state superpositions. , 1988, Physical review letters.

[18]  L. Frunzio,et al.  Autonomously stabilized entanglement between two superconducting quantum bits , 2013, Nature.

[19]  Philippe Grangier,et al.  Generation of optical ‘Schrödinger cats’ from photon number states , 2007, Nature.

[20]  L Frunzio,et al.  An RF-Driven Josephson Bifurcation Amplifier for Quantum Measurements , 2003, cond-mat/0312623.

[21]  L. Davidovich,et al.  Method for Direct Measurement of the Wigner Function in Cavity QED and Ion Traps , 1997 .

[22]  S. Girvin,et al.  Strong coupling of a single photon to a superconducting qubit using circuit quantum electrodynamics , 2004, Nature.

[23]  C. C. Bultink,et al.  Feedback control of a solid-state qubit using high-fidelity projective measurement. , 2012, Physical review letters.

[24]  A. N. Korotkov,et al.  Stabilizing Rabi oscillations in a superconducting qubit using quantum feedback , 2012, Nature.

[25]  J M Gambetta,et al.  Measurement-induced qubit state mixing in circuit QED from up-converted dephasing noise. , 2012, Physical review letters.

[26]  Victor V. Albert,et al.  Dynamically protected cat-qubits: a new paradigm for universal quantum computation , 2013, 1312.2017.

[27]  S. Girvin,et al.  Cavity-assisted quantum bath engineering. , 2012, Physical review letters.

[28]  Alexandre Blais,et al.  Qubit-photon interactions in a cavity: Measurement-induced dephasing and number splitting , 2006 .

[29]  G. C. Hilton,et al.  Amplification and squeezing of quantum noise with a tunable Josephson metamaterial , 2008, 0806.0659.

[30]  Mark Dykman,et al.  Fluctuations in nonlinear systems near bifurcations corresponding to the appearance of new stable states , 1980 .

[31]  Luigi Frunzio,et al.  Black-box superconducting circuit quantization. , 2012, Physical review letters.

[32]  R. J. Schoelkopf,et al.  Tracking photon jumps with repeated quantum non-demolition parity measurements , 2013, Nature.

[33]  Olivier Buisson,et al.  Junction fabrication by shadow evaporation without a suspended bridge , 2011, Nanotechnology.

[34]  L. DiCarlo,et al.  Fast reset and suppressing spontaneous emission of a superconducting qubit , 2010, 1003.0142.

[35]  C. Monroe,et al.  A “Schrödinger Cat” Superposition State of an Atom , 1996, Science.