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

Department of Applied Physics, Centre of Excellence in Quantum Technology, QTF, KVANTTI – Superconducting Qubits and Circuit QED

Superadiabatic population transfer in a three-level superconducting circuit

Publishing year: 2019 Science Advances
Quantum Nanomechanics, Department of Applied Physics, Centre of Excellence in Quantum Technology, QTF, KVANTTI – Superconducting Qubits and Circuit QED

Revealing hidden quantum correlations in an electromechanical measurement

Publishing year: 2018 Physical Review Letters
Department of Applied Physics, Centre of Excellence in Quantum Technology, QTF, KVANTTI – Superconducting Qubits and Circuit QED

Non-local parity measurements and the quantum pigeonhole effect

Publishing year: 2018 Entropy
Department of Applied Physics, Centre of Excellence in Quantum Technology, QTF, KVANTTI – Superconducting Qubits and Circuit QED, NANO – Quantum Circuits and Correlations

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

Publishing year: 2018 npj Quantum Information
Department of Applied Physics, KVANTTI – Superconducting Qubits and Circuit QED, Centre of Excellence in Quantum Technology, QTF, Multiscale Statistical and Quantum Physics

Multilevel Effects in a Driven Generalized Rabi Model

Publishing year: 2018 Journal of Low Temperature Physics
Centre of Excellence in Quantum Technology, QTF, KVANTTI – Superconducting Qubits and Circuit QED, Department of Applied Physics

Cross-coupling effects in circuit-QED stimulated Raman adiabatic passage

Publishing year: 2018 Journal of Physics: Conference Series
Department of Applied Physics, Centre of Excellence in Quantum Technology, QTF, KVANTTI – Superconducting Qubits and Circuit QED

Optimal superadiabatic population transfer and gates by dynamical phase corrections

Publishing year: 2018 Quantum Science and Technology
Department of Applied Physics, KVANTTI – Superconducting Qubits and Circuit QED, Centre of Excellence in Quantum Technology, QTF

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

Publishing year: 2018 Physica Scripta
Department of Applied Physics, KVANTTI – Superconducting Qubits and Circuit QED, Centre of Excellence in Quantum Technology, QTF

Quantum metrology with a transmon qutrit

Publishing year: 2018 Physical Review A
Department of Applied Physics, Centre of Excellence in Quantum Technology, QTF, KVANTTI – Superconducting Qubits and Circuit QED

Experiments with a transmon artificial atom - state manipulation and detection of magnetic fields

Publishing year: 2018
More information on our research in the Research database.
Research database

Research group members

Gheorghe-Sorin Paraoanu

Gheorghe-Sorin Paraoanu

Department of Applied Physics
Senior University Lecturer

Miika-Matias Haataja

Department of Applied Physics
Doctoral Candidate

Lauri Tuominen

Department of Applied Physics
Research Assistant

Shruti Dogra

Department of Applied Physics
Postdoctoral Researcher
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