Funding period: 2021 – 2024

Project leader: Wolfgang Belzig

Scientific staff: Matthias Hübler, Niklas Rohling, Masha Seyed Heydari

Former members: Felicitas Hellbach, Danilo Nikolic, Dennis Wuhrer

We theoretically investigate the interaction of engineered quantum fields with electronic and spintronic quantum transport. First, we address tunneling through sub-nanometer gaps initiated by ultrashort light pulses, causing a subcycle dynamics in the attosecond range due to the high nonlinearity. Second, we ask how the quantum information of a squeezed magnonic field is transformed into electronic current and how it can be detected via correlations. Both topics make heavy use of nonequilibrium field theoretical methods by using Keldysh path integrals.

List of publications

Current preprints

• Thermodynamic uncertainty relations in superconducting junctions
  D. C. Ohnmacht, J. C. Cuevas, W. Belzig, R. López, J. S. Lim, K. W. Kim
  arXiv:2408.01281 - published 2 August 2024
   
• Non-hermitian topology in multiterminal superconducting junctions
  D. C. Ohnmacht, V. Wilhelm, H. Weisbrich, W. Belzig
  arXiv:2408.01289 - published 2 August 2024
   
• Dynamical renormalisation of a spin Hamiltonian via high-order nonlinear magnonics
  C. Schoenfeld, L. Feuerer, D. Wuhrer, W. Belzig, A. Leitenstorfer, D. Juraschek, and D. Bossini
  arXiv:2310.19667 - published 30 October 2023
  also related to project A01 and B07

2024

• Dipole–dipole-interaction-induced entanglement between two-dimensional ferromagnets
  D. Wuhrer, N. Rohling, and W. Belzig
  Appl. Phys. Lett. 125, 022404 - published 9 July 2024

2023

• Magnon squeezing in conical spin spirals
  D. Wuhrer, L. Rózsa, U. Nowak, and W. Belzig
  Phys. Rev. Research 5, 043124 – published 6 November 2023
  also related to project B02 and B06
   
• Microwave-induced conductance replicas in hybrid Josephson junctions without Floquet—Andreev states
  D. Z. Haxell, M. Coraiola, D. Sabonis, M. Hinderling, S. C. ten Kate, E. Cheah, F. Krizek, R. Schott, W. Wegscheider, W. Belzig, J. C. Cuevas, and F. Nichele 
  Nat Commun 14, 6798 - published 26 October 2023
  also related to project A02
  ​​​​​​​
• ​​​​​​​Phase-engineering the Andreev band structure of a three-terminal Josephson junction​​​​​​​
  M. Coraiola, D. Z. Haxell, D. Sabonis, H. Weisbrich, A. E. Svetogorov, M. Hinderling, S. C. ten Kate, E. Cheah, F. Krizek, R. Schott, W. Wegscheider, J. C. Cuevas, W. Belzig, and F. Nichele
  Nat Commun 14, 6784 - published 25 October 2023
  also related to project A02
   
• Microwave excitation of atomic scale superconducting bound states
  J. Siebrecht, H. Huang, P. Kot, R. Drost, C. Padurariu, B. Kubala, J. Ankerhold, J. C. Cuevas, and C. R. Ast
  Nat. Commun. 14, 6794 - published 25 October 2023
  also related to project A02
   
• Electrical detectability of magnon-mediated spin current shot noise
  L. Siegl, M. Lammel, A. Kamra, H. Huebl, W. Belzig, and S. T. B. Goennenwein
  Phys. Rev. B 108, 144420 – published 18 October 2023
  also related to project B01
   
• Full counting statistics of ultrafast quantum transport
  M. Hübler and W. Belzig
  Appl. Phys. Lett. 123, 034006 - published 17 July 2023
   
• Light emission in delta-T-driven mesoscopic conductors
  M. Hübler and W. Belzig
  Phys. Rev. B 107, 155405 - published 6 April 2023

2022

• Magnon-cooparons in magnet-superconductor hybrids
  I.V. Bobkova, A.M. Bobkov, A. Kamra, and W. Belzig
  Commun. Mater. 3, 95 - published 2 December 2022
   
• Signature of resonant modes in radiative heat current noise spectrum
  J. L. Wise, N. Roubinowitz, W. Belzig, and D. M. Basko
  Phys. Rev. B 106, 165407 – published 10 October 2022
   
• Quantum-correlated photons generated by nonlocal electron transport
  F. Hellbach, F. Pauly, W. Belzig, and G. Rastelli
  Phys. Rev. B 105, L241407 – published 17 June 2022
  also related to C02
   
• Theory of quantum entanglement and structure of the two-mode squeezed antiferromagnetic magnon vacuum
  D. Wuhrer, N. Rohling, and W. Belzig
  Phys. Rev. B 105, 054406 – published 8 February 2022

2021

• Conservation laws in quantum noninvasive measurements
  S. Sołtan, M. Frączak, W. Belzig, and A. Bednorz
  Phys. Rev. Research 3, 013247 – published 17 March 2021
   
• Temperature-dependent spin transport and current-induced torques in superconductor-ferromagnet heterostructures
  M. Müller, L. Liensberger, L. Flacke, H. Huebl, A. Kamra, W. Belzig, R. Gross, M. Weiler, and M. Althammer
  Phys. Rev. Lett. 126, 087201 – published 22 February 2021

Further Publications 

• Continuous-Variable Entanglement Test in Driven Quantum Contacts

  H. Zhan, M. Vanević, and W. Belzig
  Phys. Rev. Lett. 122, 236801 – published 12 June 2019

• Non-classical current noise and light emission of an ac-driven tunnel junction
  H. Zhan, G. Rastelli, and W. Belzig
  New J. Phys.  22, 053035 - published 21 May 2020
   
• Dynamical Coulomb Blockade as a Local Probe for Quantum Transport
  J. Senkpiel, J. C. Klöckner, M. Etzkorn, S. Dambach, B. Kubala, W. Belzig, A. L. Yeyati, J. C. Cuevas, F. Pauly, J. Ankerhold, C. R. Ast, and K. Kern
  Phys. Rev. Lett. 124, 156803 – published 16 April 2020
   
• Super-Poissonian Shot Noise of Squeezed-Magnon Mediated Spin Transport

  A. Kamra and W. Belzig
  Phys. Rev. Lett. 116, 146601 – published 8 April 2016

• Spin Pumping and Shot Noise in Ferrimagnets: Bridging Ferro- and Antiferromagnets
  A. Kamra and W. Belzig
  Phys. Rev. Lett. 119, 197201 – published 6 November 2017
   
• Spin Current Cross-Correlations as a Probe of Magnon Coherence
  Scott A. Bender, Akashdeep Kamra, Wolfgang Belzig, and Rembert A. Duine
  Phys. Rev. Lett. 122, 187701 – published 6 May 2019
   
• Exchange-Enhanced Ultrastrong Magnon-Magnon Coupling in a Compensated Ferrimagnet
  L. Liensberger, A. Kamra, H. Maier-Flaig, S. Geprägs, A. Erb, S. T. B. Goennenwein, R. Gross, W. Belzig, H. Huebl, and M. Weiler
  Phys. Rev. Lett. 123, 117204 – published 13 September 2019
   
• Antiferromagnetic magnons as highly squeezed Fock states underlying quantum correlations
  A. Kamra, E. Thingstad, G. Rastelli, R. A. Duine, A. Brataas, W. Belzig, and A. Sudbø
  Phys. Rev. B 100, 174407 – published 5 November 2019
   
• Overbias Light Emission due to Higher-Order Quantum Noise in a Tunnel Junction
  F. Xu, C. Holmqvist, and W. Belzig
  Phys. Rev. Lett. 113, 066801 – published 5 August 2014
   
• Quantum Coherent Multielectron Processes in an Atomic Scale Contact
  P.-J. Peters, F. Xu, K. Kaasbjerg, G. Rastelli, W. Belzig, and R. Berndt
  Phys. Rev. Lett. 119, 066803 – published 10 August 2017