Department of Applied Physics

Superconducting Qubits and Circuit QED (KVANTTI)

Out group is doing research in fields of quantum information and quantum-level effects in superconducting devices, quantum coherent matter, and interaction of electromagnetic fields with nano-structured materials.
Artistic impression of the sample, the pulse sequence, and the density matrix. Image by Antti Paraoanu.

We are a part of the effort in nanoelectronics in the Low Temperature Laboratory, Department of Applied Physics

Group leader

Dr. Sorin Paraoanu

Research

Superconducting qubits and circuit QED

Our group focuses on the study of quantum effects in superconducting circuits comprising qubits and resonators. This is a remarkably versatile experimental platform, allowing us to dive into fundamental physical phenomena and, in the long term, aiming at applications such as quantum computers and simulators.

Some of our topics of interest:

  • Quantum state control of superconducting qubits using microwave pulses. See the trajectories on the Bloch sphere shown above; a movie is available here<https://ltl.tkk.fi/wiki/images/0/02/Trajectories.ogv>
  • Entanglement and dissipation
  • Frequency modulation effects with superconducting qubits
  • Parametric modulation of superconducting circuits and the dynamical Casimir effect
  • Architectures for quantum computing and quantum simulation

Microwave photonics

The high-frequency measurement techniques for the work on superconducting circuits can be employed in other contexts as well. Novel materials have recently been fabricated using nanotechnology. Our goal is to understand how these new types of materials, placed in cavities or in transmission lines, interact with microwave fields.

Some of our topics of interest:

  • Novel methods for extracting the microwave permittivity and permeability using coaxial air lines
  • Carbon nanotubes in electromagnetic cavities

Quantum coherent matter

We are interested in phenomena related to tunnelling in Bose-Einstein condensates, and the properties of the phase of the order parameter. We have been investigating many-body fragmented states realized with bosonic atoms in double-well traps as well as Josephson effects in fermionic gases.

Facilities

The Kvantti group is part of the Low Temperature Laboratory in the Department of Applied Physics. We are located in Nanotalo. We have immediate access to the nanofabrication equipment in the clean rooms of Micronova and the national research infrastructure OtaNano, including the Low Temperature Laboratory and imaging facilities in the Nanomicroscopy Center.

GMW 5403 room-temperature electromagnet

For measurements at room temperature in a magnetic field, we employ a GMW 76mm electromagnet model 5403 with a Sorensen DKM40-75E power supply. This device is used for testing various samples in magnetic fields and for the characterization of nanomagnetic composites in the microwave range.

  • Specifications: pole gap = 0-86 mm; pole diameter = 76 mm; maximum field = 1.5 T; power supply current = 0-75 A; power supply voltage = 0-40 V.

LTL - Dry dilution refrigerators

Dry dilution refrigerators

Services
Image: Unto Rautio

Low Temperature Laboratory

The Low Temperature Laboratory at Aalto University is one of the world centres in ultra low temperature physics and technology. The leading position is based on vigorous in-house development and construction of sub-mK refrigerators.

OtaNano

Latest publications

Listening to the quantum vacuum

Gheorghe Sorin Paraoanu, Göran Johansson 2020 Europhysics News

Simulating Spin Chains Using a Superconducting Circuit

Antti Vepsalainen, Gheorghe Sorin Paraoanu 2020 Advanced Quantum Technologies

Roadmap on STIRAP applications

Klaas Bergmann, Hanns-Christoph Naegerl, Cristian Panda, Gerald Gabrielse, Eduard Miloglyadov, Martin Quack, Georg Seyfang, Gunther Wichmann, Silke Ospelkaus, Axel Kuhn, Stefano Longhi, Alexander Szameit, Philipp Pirro, Burkard Hillebrands, Xue-Feng Zhu, Jie Zhu, Michael Drewsen, Winfried K. Hensinger, Sebastian Weidt, Thomas Halfmann, Hai-Lin Wang, Gheorghe Sorin Paraoanu, Nikolay V. Vitanov, Jordi Mompart, Thomas Busch, Timothy J. Barnum, David D. Grimes, Robert W. Field, Mark G. Raizen, Edvardas Narevicius, Marcis Auzinsh, Dmitry Budker, Adriana Palffy, Christoph H. Keitel 2019 Journal of Physics B: Atomic, Molecular and Optical Physics

Photon blockade and the quantum-to-classical transition in the driven-dissipative Josephson pendulum coupled to a resonator

I. Pietikäinen, J. Tuorila, D. S. Golubev, G. S. Paraoanu 2019 Physical Review A

Superadiabatic population transfer in a three-level superconducting circuit

Antti Vepsäläinen, Sergey Danilin, Gheorghe Sorin Paraoanu 2019 Science Advances

Experimental state control by fast non-Abelian holonomic gates with a superconducting qutrit

S. Danilin, A. Vepsäläinen, G. S. Paraoanu 2018 Physica Scripta

Quantum-enhanced magnetometry by phase estimation algorithms with a single artificial atom

S. Danilin, A. V. Lebedev, A. Vepsalainen, G. B. Lesovik, G. Blatter, G. S. Paraoanu 2018 npj Quantum Information

Revealing hidden quantum correlations in an electromechanical measurement

Caspar Ockeloen-Korppi, Erno Damskägg, Gheorghe-Sorin Paraoanu, Francesco Massel, Mika Sillanpää 2018 Physical Review Letters
More information on our research in the Research database.
Research database
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