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Superconducting platforms for quantum information and quantum simulations

Superconducting platforms have recently attracted much interest as possible candidates for the implementation of quantum computers. On the one hand the coherence of the superconducting state can be exploited to reach long dephasing times, on the other hand superconducting based qubits and other circuit elements can be fabricated by well established lithographic methods.
Additionally, superconducting systems containing linear and nonlinear elements. e.g. resonators and qubits, are used nowadays to simulate properties of complex quantum systems.
In our works we focus on the impact of dissipative environments on the coherence properties of superconducting-based circuits and on the possibility to tune their properties by intense microwave drive.  Recently, we investigated transmission spectra of the spin-boson model and of the Rabi model realized in superconducting platforms.

Image - Source: Governale et al. Chem. Phys. 268, 273 (2001)

Caption for coupled qubit figure
A register of many charge qubits coupled to a common inductor L. In case (a) the qubits are subject to a common dissipative environment; in configuration (b) each qubit is coupled to its own oscillator bath.

See some key publications:

Transmission spectra of an ultrastrongly coupled qubit-dissipative resonator system
Luca Magazzù und Milena Grifoni
Journal of Statistical Mechanics: Theory and Experiment 104002 (2019)

Probing the strongly driven spin-boson model in a superconducting quantum circuit
Luca Magazzù, P. Forn-Díaz, R. Belyansky, J.-L. Orgiazzi, M. A. Yurtalan, M. R. Otto, A. Lapascu, C. M. Wilson und Milena Grifoni
Nature Communications 9, 1403 (2018)

Dynamics of a qubit coupled to a dissipative nonlinear quantum oscillator: An effective-bath approach
Carmen Vierheilig, Dario Bercioux und Milena Grifoni
Phys. Rev. A 83, 012106 (2011)

Qubit-oscillator system: An analytical treatment of the ultrastrong coupling regime
Johannes Hausinger und Milena Grifoni
Phys. Rev. A 82, 062320 (2010)

Dissipative dynamics of a qubit coupled to a nonlinear oscillator
Carmen Vierheilig, Johannes Hausinger und Milena Grifoni
Phys. Rev. A 80, 052331 (2009)

Decoherence and dephasing in coupled Josephson qubits
M. Governale, Milena Grifoni und G. Schön
Chemical Physics 268, 273-283 (2001)


QTS Research - Working Group Grifoni

Quantum Transport and Spintronics

A two-state system

Institut I - Theoretische Physik
Universität Regensburg
Universitätsstraße 31
D-93053 Regensburg