IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication.
Jochen Braumüller1 , Andre Schneider1 and Martin P. Weides1,2 1Karlsruhe Institute of Technology (KIT) 2Johannes Gutenberg University Mainz
September 29th 2015, Burg Warberg, Kryo 2015 Experiments with superconducting qubits multi-photon dressing, qubits with magnetic coupling IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication.
. Introduction . Anharmonic many-level quantum circuit . Dispersive shifts, power spectroscopy, Rabi sidebands . Concentric transmons
. Gradiometric, fast tunable, site-selective sz coupling . Ongoing . QuantumMagnonics: quantum limited detection of dynamics in ferromagnets
2 Martin Weides KIT & JGU Mainz IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication.
Bits and Quantum Bits Today’s chips
Integrated circuit Classical bit 1-4 GHz clock rate Multi-core processsor 1 1 0 1 1 0 1st transistor 1947
Quantum bit (qubit) S = 1/2
Superposition & entanglement: 2N- dim. Hilbert space
Parallel processing (Shor factoring, Grover search, Q-simulation)
3 Martin Weides KIT & JGU Mainz IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Transmons: capacitively shunted Josephson junction Anharmonic oscillator
Non-linear, tunable LC oscillator Two lowest levels Bloch sphere
Magnetic flux changes LJ(f)
4 Martin Weides KIT & JGU Mainz IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication.
. Introduction . Anharmonic many-level quantum circuit . Dispersive shifts, power spectroscopy, Rabi sidebands . Concentric transmons
. Gradiometric, fast tunable, site-selective sz coupling . Ongoing . QuantumMagnonics: quantum limited detection of dynamics in ferromagnets
5 Martin Weides KIT & JGU Mainz IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Anharmonic many-level quantum circuit
transmon qubit: weak anharmonicity
Consider higher quantum levels efficient & robust enhanced security of key quantum quantum gates distribution in quantum simulation cryptography spin-½ ↔ two levels spin-1 ↔ three levels
Neeley Nat. Phys. 4, 523 (2008) Bruß PRL 88, 127901 (2002) Paraoanu JLTP 175, 633 (2014) Fedorov Nat. 481, 170 (2011) Cerf PRL 88, 127902 (2002)
6 Martin Weides KIT & JGU Mainz IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Experiment
. microstrip geometry Sandberg et al. APL 102, 072601 (2013) . overlap Josephson junction
. transmon regime: ≫ ⇒ ~0.05 Koch et al. PRA 76, 042319 (2007) . spectroscopic measurements Blais et al. PRA 69, 062320 (2004) . VNA readout tone . microwave drive/probe tone Braumüller et al.,PRB 91, 7 Martin Weides KIT & JGU Mainz 054523 (2015) IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Power spectroscopy – multiphoton transitions
Braumüller et al.,PRB 91, 8 Martin Weides KIT & JGU Mainz 054523 (2015) IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Power spectroscopy – multiphoton transitions
Multi-photon transitions
. Six bound states in Josephson potential . Dispersive shift scales with excitation number ‹n›
Braumüller et al.,PRB 91, 9 Martin Weides KIT & JGU Mainz 054523 (2015) IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Dispersive shift by higher levels effective Hamiltonian
Induced by resonator Induced by qubit
Braumüller et al.,PRB 91, 10 Martin Weides KIT & JGU Mainz 054523 (2015) IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Dispersive shift by higher levels Rotating-wave Hamiltonian
Induced by resonator Induced by qubit Spectroscopy: equal population of 0 , * Relative resonator shift c 0j 2 | ) w ( 21 |S
g01 = 115 MHz D≈1 GHz Braumüller et al.,PRB 91, 11 Martin Weides KIT & JGU Mainz 054523 (2015) IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Power spectroscopy – data & simulation
measurement
simulation
Braumüller et al.,PRB 91, 12 Martin Weides KIT & JGU Mainz 054523 (2015) IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Multiphoton dressing − , Rabi sidebands Strong drive Sweep drive amp, probe freq.
measurement simulation
. 0 , 2 degenerate in rotating frame dressing . Probing level structure (in rotating frame) with weak probe tone
Braumüller et al.,PRB 91, 13 Martin Weides KIT & JGU Mainz 054523 (2015) IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Multiphoton dressing – pumping the | ⟩-level Sweep drive & probe freqs.
measurement
simulation
Dynamical coupling of levels by probe tone avoided crossing, Autler-Townes doublet Braumüller et al.,PRB 91, 14 Martin Weides KIT & JGU Mainz 054523 (2015) IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication.
. Introduction . Anharmonic many-level quantum circuit . Dispersive shifts, power spectroscopy, Rabi sidebands . Concentric transmons
. Gradiometric, fast tunable, site-selective sz coupling . Ongoing . QuantumMagnonics: quantum limited detection of dynamics in ferromagnets
15 Martin Weides KIT & JGU Mainz IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication.
Advancing coherence in superconducting qubits
Devoret, Schoelkopf Science 339, 116 (2013) . Long coherence: scalable quantum computation, error correction . Useful: high experimental flexibility by fast flux tuning of levels
16 Martin Weides KIT & JGU Mainz IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication.
Novel design: Tunable, concentric transmon qubit (2d)
Coherence limited by energy relaxation . Minimize surface/interface TLS loss microstrip design . radiative decay reduce qubit‘s dipole moment (symmetry)
. Fast (ns) tunability
. Side-selective sz and sx couplings
17 Martin Weides KIT & JGU Mainz Braumüller et al., arXiv:1509.08014 IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Concentric transmon qubit – flux spectroscopy
EJ, EC do not match conventional transmon theory Koch et al. PRA 76, 042319 (2007) Modified Hamiltonian considering geometric inductance
18 Martin Weides KIT & JGU Mainz Braumüller et al., arXiv:1509.08014 IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Pulsed measurements – Rabi oscillations )
. |0〉 a.u 11 (
arg |1〉 D ( )
19 Martin Weides KIT & JGU Mainz Braumüller et al., arXiv:1509.08014 IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Pulsed measurements – Lifetime and coherence
P1 P0 echo T2=10.2 s T1=9.1 s
P0 P1 0 10 20 30 0 10 20 30 Dt [s] Dt [s]
20 Martin Weides KIT & JGU Mainz Braumüller et al., arXiv:1509.08014 IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Pulsed measurements – fast z (energy splitting)-control
21 Martin Weides KIT & JGU Mainz Braumüller et al., arXiv:1509.08014 IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication.
XYZ-tomography, benchmarking, state control
Full sx,sy,sz control, SSB-mixing, shaped pulses (DRAG) Gate benchmarking (99.54%) Precise qubit state control Monitor decay = (|0〉 + |1〉) (x-axis)
22 Martin Weides KIT & JGU Mainz Schneider MA thesis (2015) IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication.
XYZ-tomography, benchmarking, state control
Full sx,sy,sz control, SSB-mixing, shaped pulses (DRAG) Gate benchmarking (99.54%) Precise qubit state control Monitor decay = (|0〉 + |1〉) (x-axis)
23 Martin Weides KIT & JGU Mainz Schneider MA thesis (2015) IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication.
XYZ-tomography, benchmarking, state control
Full sx,sy,sz control, SSB-mixing, shaped pulses (DRAG) Gate benchmarking (99.54%) Precise qubit state control Monitor decay = (| 〉 + | 〉) (x-axis)
24 Martin Weides KIT & JGU Mainz Schneider MA thesis (2015) IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication.
. Introduction . Anharmonic many-level quantum circuit . Dispersive shifts, power spectroscopy, Rabi sidebands . Concentric transmons
. Gradiometric, fast tunable, site-selective sz coupling . Ongoing . QuantumMagnonics: quantum limited detection of dynamics in ferromagnets
25 Martin Weides KIT & JGU Mainz IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Magnonics: spin waves in nanostructures
Magnon: quantized spin wave excitation Future information technology (e.g. spin-torque oscillator, spin-wave propagation control for logic)
Slavin et al., Nat. Nanotech. 4, 479 (2009) Vogt et al., Nat. Commun. 5, 3727 (2014) Linewidth Δf > 1 MHz Attenuation length ~10 um Strong magnon damping: magnon/phonon/electron scattering Grand challenge: To understand physics, single magnon information needed!
26 Martin Weides KIT & JGU Mainz IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. How to probe a single magnon?
. Quantum ground state (T=10 mK) . Ultra-low power spectroscopy, coherent coupling . How to achieve? Extend magnon to artificial spin!
Access magnon lifetime and coherence via coherent coupling
Use concentric transmon with sz coupling
27 Martin Weides KIT & JGU Mainz IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication. Summary
. Introduction . Anharmonic many-level quantum circuit . Dispersive shifts, power spectroscopy, Rabi sidebands . Concentric transmons
. Gradiometric, fast tunable, site-selective sz coupling . Ongoing . QuantumMagnonics: quantum limited detection of dynamics in ferromagnets
28 Martin Weides KIT & JGU Mainz IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), January 2016. KRYO 2015 oral presentation. Not submitted for publication.
KIT-Team
BA MA PhD Technician Cem Kücük Lukas Grünhaupt Jochen Braumüller Lucas Radtke Oliver Hahn Julius Krause Marco Pfirrmann Marcel Langer Andre Schneider Steffen Schlör Scientists Moritz Kappeler Patrick Winkel Ping Yang Hannes Rotzinger Tomislav Piskor Max Zanner Sasha Lukashenko Patricia Stehle Alexey Ustinov Martin Weides Thank you for your attention Mainz NIST Isabelle Boventer Martin Sandberg Mathias Kläui Michael Vissers David Pappas
29 Martin Weides KIT & JGU Mainz