SiUCs-QUCOS QuantERA workshop

Contribution List

1. Pol Forn-Díaz, IFAE (SiUCs coordinator) - Welcome

23/02/2023, 09:15

2. Alba Torras, IFAE (SiUCs) - Ultrastrong coupling regime in superconducting circuits using superinductor materials

23/02/2023, 09:30

Superconducting circuits offer a versatile platform to control and study light-matter interaction beyond the strong coupling regime. In this context, qubits play the role of artificial atoms, LC resonators act as cavities and the shared capacitance or
inductance between elements define the level of coupling.
From a circuit design point of view, the coupling coefficient can be engineered to...

3. Gerhard Kirchmair, University of Innsbruck (QuCoS coordinator) - Coupling Fluxonium to a 3D circuit QED architecture - towards a dissipative cat qubit

23/02/2023, 10:00

The aim of QuCoS is to encode a quantum bit in the fundamental bosonic mode of a weakly non-linear coaxial cavity[2] and protect it from decoherence with engineered two-photon dissipation [1]. In the case of this sub-project, the cavity non-linearity is inherited from a fluxonium qubit[3], which allows us to tune the memory-ancilla interaction in situ. As recently shown, in contrast to the...

4. Ioan Pop, KIT (SiUCs) - About AlOx interfaces and Aluminum superconducting device performance

23/02/2023, 10:30

It is already well established that amorphous AlOx can host a zoo of spurious of two level systems, from positional defects to spin impurities. In this talk I will focus on other effects which can occur at the interface of AlOx with the Al electrodes in an SIS junction, or at the interface between a superconducting resonator and an in-situ grown para-Hydrogen crystal. The main conclusion of my...

5. Antoine Marquet, École Normale Superieure de Lyon (QuCoS) - Passive two-photon dissipation for bit-flip error correction of a cat code

23/02/2023, 12:00

Demonstrating Quantum Error Correction is a key step toward the realization of a large-scale quantum computer. In contrast to strategies using a register of physical qubits to store the protected logical qubit, bosonic codes offer a resource-efficient alternative to reach the same goal. In these codes, the large ensemble of physical qubits is replaced by the many energy levels of a harmonic...

6. Luca Magazzù, University of Regensburg (SiUCs) - Transmission spectra of a strongly driven, dissipative Rabi model in the USC regime

23/02/2023, 12:30

We present theoretical transmission spectra of a strongly driven, damped flux
qubit coupled to a dissipative resonator in the ultrastrong-coupling regime.
Such a qubit-oscillator system, described within a dissipative Rabi model,
constitutes the building block of superconducting circuit QED platforms. The
addition of a strong drive allows one to characterize the system properties and
study...

7. Erwan Roverc'h, École Normale Superieure de Paris (QuCos) - Cooper-pair pairing: a resource for nonlocality and qubit protection

23/02/2023, 14:30

The Josephson junction as a source of nonlinearity for superconducting circuits has become ubiquitous in quantum science and engineering. Introducing exotic circuit elements that only allow pairs of Cooper pairs to tunnel allows new properties to be uncovered, sparking interest for metrology and qubit protection. We present novel circuits obtained with an effective implementation of such an...

8. Miroslav Grajcar, Slovak Academy of Sciences (SiUCs) - The quantum-limited detectors based on superconducting weak links

23/02/2023, 15:00

In my talk I will present the design of two types of quantum-limited detectors of microwaves: a) travelling waves parametric amplifier and b) itinerant microwave photon detectors. Both designs are based on an array of superconducting nonlinear weak links.
The traveling wave parametric amplifiers are designed as coplanar waveguides with a central wire consisting of i) a high kinetic inductance...

9. Ramon Szmuk, Quantum Machines (QuCoS) - Pound locking for resonator frequency tracking and noise analysis

23/02/2023, 15:30

The Pound technique is a powerful method for determining the relative detuning between a driving oscillator and a microwave resonator, allowing to lock one to the other and perform high bandwidth characterisations of resonator noise spectra, quality factors, and other parameters.
We present resonator frequency tracking with >10kHz lock bandwidth using Quantum Machine's Octave and OPX devices,...

17. Free Time

23/02/2023, 18:00

18. Workshop dinner

23/02/2023, 20:00

13. Dorian Fraudet, Néel Institute CNRS (SiUCs) - Spontaneous three photon generation in multi-mode circuit-QED

24/02/2023, 09:30

The coupling of a single quantum system to a large number of independent degrees of freedom can display very rich physics when pushed to extreme regimes. Such a setup can be implemented using the tools of circuit-QED where an artificial atom made out of Josephson junctions is coupled to a multi-mode microwave cavity. When the coupling strength between the quantum system and the modes becomes...

12. Luiza Buimaga-Iarinca, ITIM (QuCoS) - Computational assessment of aluminium-based materials

24/02/2023, 10:00

In material manufacturing it is usually impossible to discriminate between the role and weight of each factor that may affect the structure composition at nanoscopic scale. This gap can be filled by computational modeling techniques and methods. One of the most powerful is the molecular dynamics (MD), which provides detailed information on the effect of substitutional disorder, defects,...

11. Giuseppe Falci, CNR (SiUCs) - Detecting virtual phothons in ultrastrongly coupled superconducting quantum circuits

24/02/2023, 10:30

Light-matter interaction, and understanding the fundamental physics behind, is essential for emerging quantum technologies. Solid-state devices may explore new regimes where coupling strengths are "ultrastrong", i.e. comparable to the energies of the subsystems. New exotic phenomena occur the common root of many of them being the fact that the entangled vacuum contains virtual photons. They...

15. IFAE´s lab tour

24/02/2023, 12:00

19. Departure

24/02/2023, 13:00

10. -

14. Closing session

16. Lunch (end)