Cooperative quantum phenomena in circuits with Josephson junctions: Strong driving, photon generation, and non-Gaussian noise

• Applicant: Professor Dr. Joachim Ankerhold
• Subject Area: Theoretical Condensed Matter Physics
• Term: from 2012 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 214374243

• Final Report Year: 2017

Final Report Abstract

In this project we investigated the dynamics of superconducting circuits including Josephson junctions far from equilibrium. The focus has been on circuits subject to external time-dependent fields including optimal control and on the interplay of charge transfer and electromagnetic fields in set-ups generalizing circuit quantum electrodynamics. The presence of external time-dependent control fields turns dissipative reservoirs, typically considered as detrimental to quantum effects, into resources to create and stabilize fragile quantum properties such as entanglement. A quantitative description requires a non-perturbative treatment of time dependent phenomena for open quantum systems which have thus been further developed during this project. This also allowed to attack fundamental questions of quantum thermodynamics such as work, heat, heat currents, and the impact of system-bath correlations and non-Markovian dynamics. Out of the second focus area grew the new field of Josephson photonics which can be considered as an extension of circuit quantum electrodynamics and is embedded in still broader activities to explore the quantum optics of quantum conductors in general. In collaboration with experimentalists it was shown that this class of mesoscopic systems offers a rich playground to study phenomena such as the transition from sequential to coherent Cooper pair transfer, quantum nonlinear dynamics, and the generation of non-classical microwave photons. Our results have direct influence on the understanding and development of new Scanning Tunneling Microscopes operating at ultra-low temperatures (covered by a press release) and the design of novel sources for quantum microwave radiation.

Publications

• Emission of non-classical radiation by inelastic Cooper pair tunneling, Phys. Rev. Lett.
  M. Westig, B. Kubala, O. Parlavecchio, Y. Mukharsky, C. Altimiras, P. Joyez, D. Vion, P. Roche, M. Hofheinz, D. Esteve, M. Trif, P. Simon, J. Ankerhold, and F. Portier
  
• Almost local generation of Einstein-Podolsky-Rosen entanglement in nonequilibrium open systems, Phys. Rev. A 88, 052321 (2013)
  R. Schmidt, J.T. Stockburger, and J. Ankerhold
  
• From Coulomb-Blockade to Nonlinear Quantum Dynamics in a Superconducting Circuit with a Resonator, Phys. Rev. Lett. 111, 247002 (2013)
  V. Gramich, B. Kubala, S. Rohrer, and J. Ankerhold
  
• Lamb shift enhancement and detection in strongly driven superconducting circuits, Phys. Rev. Lett. 113, 027001 (2014)
  V. Gramich, S. Gasparinetti, P. Solinas, and J. Ankerhold
  
• Optimal Control theory with arbitrary superpositions of waveforms, J. Phys. A: Math. Theor. 47, 495002 (2014)
  S. Meister, J.T. Stockburger, R. Schmidt, and J. Ankerhold
  
• Entanglement generation through local field and quantum dissipation, Phys. Scr. T 165, 014020 (2015)
  J.T. Stockburger, R. Schmidt, and J. Ankerhold
  
• Resonators coupled to voltage-biased Josephson junctions: From linear response to strongly driven nonlinear oscillations, Phys. Rev. B 92, 174532 (2015)
  S. Meister, M. Mecklenburg, V. Gramich, J.T. Stockburger, J. Ankerhold, and B. Kubala
  
• Work and heat for two-level systems in dissipative environments: Strong driving and non-Markovian dynamics, Phys. Rev. B 91, 224303 (2015)
  R. Schmidt, M. F. Carusela, J. P. Pekola, S. Suomela, and J. Ankerhold
  
• Exact propagation of open quantum systems in a systemreservoir context, Europhys. Lett. 115, 40010 (2016)
  J. T. Stockburger
  
• Sensing the quantum limit in scanning tunnelling spectroscopy, Nature Communications 7, 13009 (2016)
  C. R. Ast, B. Jack, J. Senkpiel, M. Eltschka, M. Etzkorn, J. Ankerhold, and K. Kern
  
• Currents and fluctuations of quantum heat transport in harmonic chains, New J. Phys. 19, 053013 (2017)
  T. Motz, J. Ankerhold, and J. Stockburger
  
• Thermodynamic deficiencies of some simple Lindblad operators, Fortschr. Phys. 65, 1600067 (2017)
  J. T. Stockburger and T. Motz