A5068415966- Mechanical and Optical Resonators
- Quantum Information and Cryptography
- Acoustic Wave Resonator Technologies
- Quantum and electron transport phenomena
- Quantum Computing Algorithms and Architecture
- Neural Networks and Reservoir Computing
- Cold Atom Physics and Bose-Einstein Condensates
- Physics of Superconductivity and Magnetism
- Photonic and Optical Devices
- Advanced Fiber Laser Technologies
- Quantum, superfluid, helium dynamics
- Superconducting and THz Device Technology
- Quantum Mechanics and Applications
- Iron-based superconductors research
- Optical Network Technologies
- GaN-based semiconductor devices and materials
- Ultrasonics and Acoustic Wave Propagation
- Force Microscopy Techniques and Applications
- Advanced MEMS and NEMS Technologies
- Superconductivity in MgB2 and Alloys
Chalmers University of Technology
2021-2025
VTT Technical Research Centre of Finland
2024
Aalto University
2018-2022
Hosting nonclassical states of light in three-dimensional microwave cavities has emerged as a promising paradigm for continuous-variable quantum information processing. Here we experimentally demonstrate high-fidelity generation range Wigner-negative useful computation, such Schrödinger-cat states, binomial Gottesman-Kitaev-Preskill well cubic phase states. The latter have been long sought after optics and never achieved before. We use sequence interleaved selective number-dependent...
Mechanical resonators are a promising way for interfacing qubits in order to realize hybrid quantum systems that offer great possibilities applications. can have very long energy lifetimes, and they be further interfaced other systems. Moreover, integration of mechanical oscillator with creates potential platform exploration physics macroscopic degrees freedom. Utilization high overtone bulk acoustic coupled superconducting is an intriguing towards these goals. These exhibit combination...
Atom-photon bound states arise from the coupling of quantum emitters to band edge dispersion-engineered waveguides. Thanks their tunable-range interactions, they are promising building blocks for simulators. Here, we study dynamics an atom-photon state emerging a frequency-tunable emitter—a transmon-type superconducting circuit—to microwave metamaterial. Employing precise temporal control over frequency detuning emitter edge, examine transition adiabatic nonadiabatic behavior in formation...
The studies of mechanical resonators in the quantum regime not only provide insight into fundamental nature mechanics massive objects, but also introduce promising platforms for novel hybrid technologies. Here we demonstrate a configurable interaction between superconducting qubit and many acoustic modes regime. Specifically, show how consecutive Landau-Zener-St\"uckelberg (LZS) tunneling type transitions, which take place when system is tuned through an avoided crossing coupled energy...
Multimode bulk acoustic systems show promise for use in superconducting quantum computation. They can serve as a medium term memory storage, with exceptional coherence times demonstrated, and they exhibit mode density that is physically highly compact. Here we experimentally demonstrate accessing individual modes without being hindered by the uniform frequency spacing of modes. We sideband control where low-frequency modulation applied to transmon qubit energy. The amplitude defines...
Studies of micromechanical and acoustic modes in the quantum regime have shed light on properties massive objects. Integrating these systems into superconducting circuits shows great promise for applications as memory elements, bosonic codes, or frequency conversion. To this end, investigation nonclassical degrees freedom is critical also applications. Here, we investigate a strongly driven system consisting transmon qubit interacting with high-overtone bulk resonator. We observe multiphonon...
Bosonic quantum error correcting codes are primarily designed to protect against single-photon loss. To correct for this type of error, one can encode the logical qubit in code spaces with a definite photon parity, such as cat or binomial codes. Error correction requires recovery operation that maps states -- which have opposite parity back onto states. Here, we realize collection photon-number-selective, simultaneous addition operations on bosonic mode, microwave cavity, assisted by...
Numerous applications, from industrial non-destructive imaging through ultra-sensitive photon counting to various implementations of solid-state quantum computers require low temperatures for their sensor and processor chips. Replacing the bulky cryo-liquid based cooling stages cryo-enabled instruments by chip scale refrigeration is envisioned disruptively reduce system size similarly as microprocessors did computers. Chip has been demonstrated with electronic refrigerators on tunnel...
Detecting quasiparticle tunneling events in superconducting circuits provides information about the population and dynamics of non-equilibrium quasiparticles. Such can be detected by monitoring changes frequency an offset-charge-sensitive qubit. This has so far been performed Ramsey interferometry assisted a readout resonator. Here, we demonstrate detector based on qubit directly coupled to waveguide. We measure number parity island probing coherent scattering microwave tone, offering...
Atom-photon bound states arise from the coupling of quantum emitters to band edge dispersion-engineered waveguides. Thanks their tunable-range interactions, they are promising building blocks for simulators. Here, we study dynamics an atom-photon state emerging a frequency-tunable emitter - transmon-type superconducting circuit microwave metamaterial. Employing precise temporal control over frequency detuning edge, examine transition adiabatic non-adiabatic behavior in formation and its...
Homo- and heterodyne detection are fundamental techniques for measuring propagating electromagnetic fields. However, applying these to stationary fields confined in cavities poses a challenge. As way overcome this challenge, we propose use repeated indirect measurements of two-level system interacting with the cavity. We demonstrate numerically that proposed measurement scheme faithfully reproduces statistics homo- or detection. The can be implemented various physical architectures,...
We demonstrate the use of coherent-state quantum process tomography (csQPT) for a bosonic-mode superconducting circuit. have enhanced our methodology over previous implementations csQPT by leveraging Kraus operators and constrained gradient descent to learn underlying process. show results method characterizing logical gate implemented using displacement selective number-dependent arbitrary phase operations on an encoded qubit. Our allows reconstruction larger Hilbert space rather than being...
Replacing the bulky cryoliquid-based cooling stages of cryoenabled instruments by chip-scale refrigeration is envisioned to disruptively reduce system size similar microprocessors did for computers. Electronic refrigerators based on superconducting tunnel junctions have been anticipated provide a solution, but reaching necessary above 1-K operation temperature range has remained goal out reach several decades. We show efficient electronic...
Encoding quantum information into superpositions of multiple Fock states a harmonic oscillator can provide protection against errors, but it comes with the cost requiring more complex gates that need to address simultaneously. Therefore, characterizing process fidelity these also becomes challenging. Here, we demonstrate use coherent-state tomography (csQPT) for bosonic-mode superconducting circuit. CsQPT uses coherent as input probes in order completely characterize operation an arbitrary...
We investigate a superconducting qubit coupled to quantum acoustic system in near resonant configuration. In our we measure multiphonon transitions, whose spectrum reveals distinctly nonclassical features and thus provides direct evidence of quantization GHz sound, enabling phonon counting. Additionally, at high driving amplitude comparable the qubit-oscillator coupling, observe shift spectral lines owing dressing many transitions.
Linear bosonic modes offer a hardware-efficient alternative for quantum information processing but require access to some nonlinearity universal control. The lack of in photonics has led encoded measurement-based computing, which rely on linear operations requires resourceful ('nonlinear') states, such as cubic phase states. In contrast, superconducting microwave circuits engineerable nonlinearities suffer from static Kerr nonlinearity. Here, we demonstrate control mode composed nonlinear...
Homo- and heterodyne detection are fundamental techniques for measuring propagating electromagnetic fields. However, applying these to stationary fields confined in cavities poses a challenge. As way overcome this challenge, we propose use repeated indirect measurements of two-level system interacting with the cavity. We demonstrate numerically that proposed measurement scheme faithfully reproduces statistics homo- or at single-shot level. The can be implemented various physical...