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Title goes here. Building a superconducting quantum computer with the surface code. Matteo Mariantoni Fall INTRIQ meeting, November 5 th & 6 th 2013. t he DQM lab t eam. Collaborators: Prof. Michael J. Hartmann Heriot Watt University Prof. Frederick W. Strauch Williams College
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Title goes here Building a superconducting quantum computer with the surface code Matteo Mariantoni Fall INTRIQ meeting, November 5th & 6th 2013
the DQM lab team • Collaborators: • Prof. Michael J. Hartmann • Heriot Watt University • Prof. Frederick W. Strauch • Williams College • Prof. Adrian Lupaşcu • IQC • Prof. Christopher M. Wilson • IQC • Prof. Zbig R. Wasilewski • WIN • Dr. Austin G. Fowler • UC Santa Barbara • Prof. David G. Cory • IQC • Prof. Guo-Xing Miao • IQC • Prof. Roger G. Melko • UW • SadeghRaeisi • IQC • Yuval R. Sanders • IQC Matteo Mariantoni Principal Investigator DaryoushShiri Postdoctoral Fellow Thomas G. McConkey Doctoral Student John R. Rinehart Doctoral Student Carolyn “Cary” T. Earnest Doctoral Student JérémyBéjanin Master’s Student Corey Rae H. McRae DoctoralStudent Yousef Rohanizadegan Research Assistant
lab virtual walkthrough DR photo credit BlueFors Cryogenics Oy the lab is being setup in these very days; it will be up and running by February 2014
lab realwalkthrough the lab is being setup in these very days; it will be up and running by February 2014
on the edge nano/micro meter space nano/micro meter space milli kelvin temperature frequency time giga hertz photo credit – M. Mariantoni and E. Lucero University of California Santa Barbara
on the edge milli kelvin temperature photo credit – BlueFors Cryogenics Oy
on the edge frequency time giga hertz photo credit – M. Mariantoni and E. Lucero
superconducting quantum circuits • LCresonator
superconducting quantum circuits • LCresonator ~ 7 GHz
superconducting quantum circuits • transmission-line resonator dielectric material
superconducting quantum circuits • coplanarwaveguide resonator T1 ~ 5 ms T2~ 2T1 M. Mariantoniet al., Nature Phys. 7, 287 (2011)
superconducting quantum circuits • qubit Josephson junction → nonlinearity
superconducting quantum circuits • qubit dan ~ 200 MHz ~ 6.8 GHz ~ 7 GHz
superconducting quantum circuits • qubit junction capacitor C inductor L T1 ~ 500 ns T2 ~ 150 ns M. Mariantoniet al., Nature Phys. 7, 287 (2011)
superconducting quantum circuits • resonator+qubit+control X,Y (p, p/2); Z junction resonator capacitor C inductor L + qubit g(Cb) ~ 100 MHz 10 ns A. Blais, R.-S. Huang, A. Wallraff, S.M. Girvin, and R.J. Schoelkopf, Phys. Rev. A 69, 062320 (2004); A. Wallraffet al., Nature (London) 431, 162 (2004) M. Mariantoniet al., Nature Phys. 7, 287 (2011)
one-qubitpulses and one-qubitquantum errors • pulses • () energizes the qubitfrom to • () prepares the qubitin state • () shifts the qubitby a certain phase, • errors • bit-flip () brings the qubit from to • phase-flip () shifts the qubitfrom to • any error P.W. Shor, Phys. Rev. A 52, 2493 (1995)
create, write, re-create, zero, read entanglement M1 B Q1 Z2 Z1 Q2 M2
the CZ-p gate • qutrit qubit
the CZ-p gate • qutrit phase qubit qutrit
the CZ-p gate • qutrit-resonator interaction
the CZ-p gate • qutrit-resonator interaction
the CZ-p gate • qutrit-resonator interaction
the CZ-p gate • qutrit-resonator interaction semi-resonant resonant
the CZ-p gate • two-qubitCZ-fgate semi-resonant resonant
the CZ-p gate • two-qubitCZ-fgate semi-resonant control resonant THEORY: F. W. Strauch et al., Phys. Rev. Lett. 91, 167005 (2003) G. Haack,…, M.M.,... et al., Phys. Rev. B 82, 024514 (2010) EXPERIMENT: L. DiCarloet al., Nature (London) 460, 240-244 (2009) T. Yamamoto ,…, M.M.,... et al., Phys. Rev. B 82, 184515 (2010) target
the CZ-p gate • CZ-p gate truth table semi-resonant control resonant target
the CZ-p gate • two-qubitCZ-fgate semi-resonant resonant
the CZ-p gate • two-qubitCZ-fgate semi-resonant resonant M. Mariantoni et al., Science 334,61 (2011)
the CZ-p gate • two-qubitCZ-fgate semi-resonant resonant M. Mariantoni et al., Science 334,61 (2011)
the CZ-p gate • f-meter: Generalized Ramsey (a)
the CZ-p gate • f-meter: Generalized Ramsey (a) compensate dynamic phase varying zcmp Ramsey fringe
the CZ-p gate • f-meter: Generalized Ramsey (b)
the CZ-p gate • f-meter: Generalized Ramsey (a-b)
the CZ-p gate • f-meter: Generalized Ramsey (a-b)
the CZ-p gate • f-meter: Generalized Ramsey (a-b) f = 0.01 f = p/2 f = p
the CZ-p gate • process tomography fidelity ~70% fidelity ~60% qubit T1~500 ns, T2~150 ns
superconducting surface code A.G. Fowler, M. Mariantoni, J.M. Martinis, and A.N. Cleland, Phys. Rev. A 86, 032324 (2012) ~ 50 pages of details
2D lattice with nearest neighbor interactions A.G. Fowler, M. Mariantoni, J.M. Martinis, and A.N. Cleland, Phys. Rev. A 86, 032324 (2012) ~ 50 pages of details
surface code • data and syndrome qubit syndrome → measured data
surface code • face and vertex A.Yu. Kitaev, Annals of Physics 303, 2 (2003)
stabilizers • Z-stabilizer 1 2 3 4
stabilizers • Z-stabilizer • zeroing gate 1 2 3 4
stabilizers • Z-stabilizer • projects 1 2 3 4
stabilizers • X-stabilizer • projects 1 2 3 4
stabilizers one qubit detected by repeatedly measuring the qubit with combined and measurements qubitstate destroyed
stabilizers pair of qubits, and , detected by repeatedly measuring the pair of qubits with and measurements
stabilizers pair of qubits, and , detected by repeatedly measuring the pair of qubits with and measurements
stabilizers error detection event BUT cannot be distinguished from an error!
stabilizers • quiescent state -1 +1