A5058533447- Quantum and electron transport phenomena
- Physics of Superconductivity and Magnetism
- Superconducting and THz Device Technology
- Mechanical and Optical Resonators
- Quantum Information and Cryptography
- Semiconductor Quantum Structures and Devices
- Advanced Electrical Measurement Techniques
- Atomic and Subatomic Physics Research
- Thermal Radiation and Cooling Technologies
- Quantum Computing Algorithms and Architecture
- Terahertz technology and applications
- Quantum Mechanics and Applications
- Photonic and Optical Devices
- Power Quality and Harmonics
- Semiconductor materials and devices
- Semiconductor Lasers and Optical Devices
- Advanced Thermoelectric Materials and Devices
- Magneto-Optical Properties and Applications
- Advanced MRI Techniques and Applications
- Topological Materials and Phenomena
- Cold Atom Physics and Bose-Einstein Condensates
- Advancements in Semiconductor Devices and Circuit Design
- Microwave Engineering and Waveguides
- Advanced Thermodynamics and Statistical Mechanics
- Integrated Circuits and Semiconductor Failure Analysis
VTT Technical Research Centre of Finland
2014-2024
IQM (Finland)
2019-2023
Bluefors (Finland)
2021
The University of Adelaide
2020
Jet Propulsion Laboratory
2020
Space Information Laboratories (United States)
2020
North Carolina State University
2020
Aalto University
2020
The University of Western Australia
2020
UCLA Health
2020
Vacuum modes confined into an electromagnetic cavity give rise to attractive interaction between the opposite walls. When distance walls is changed non-adiabatically, virtual vacuum are turned real particles, i.e. photons generated out of vacuum. These effects known as static and dynamical Casimir effect, respectively. Here we demonstrate effect using a Josephson metamaterial embedded in microwave at 5.4 GHz. We achieve non-adiabatic change effective length by flux-modulation SQUID-based...
Abstract Ultra‐low‐field MRI uses microtesla fields for signal encoding and sensitive superconducting quantum interference devices detection. Similarly, modern magnetoencephalography (MEG) systems use arrays comprising hundreds of device channels to measure the magnetic field generated by neuronal activity. In this article, hybrid MEG‐MRI instrumentation based on a commercial whole‐head MEG is described. The combination ultra‐low‐field in single expected significantly reduce coregistration...
Tunable coupling of superconducting qubits has been widely studied due to its importance for isolated gate operations in scalable quantum processor architectures. Here, we demonstrate a tunable qubit-qubit coupler based on floating transmon device, which allows us place at least 2 mm apart from each other while maintaining over 50-MHz between the and qubits. In introduced tunable-coupler design, both qubit-coupler couplings are mediated by two waveguides instead relying direct capacitive...
Scaling down the dimensions of thermoacoustic sound sources (thermophones) improves efficiency by means reducing speaker heat capacity. Recent experiments with nanoscale thermophones have revealed properties which are not fully understood theoretically. We develop a Green's function formalism quantitatively explains some observed discrepancies, e.g., effect heat-absorbing substrate in proximity source. also find generic ultimate limit for thermophone efficiency. verify theory and finite...
Resonant strings are a promising concept for ultra sensitive temperature detection. We present an analytical model the sensitivity with which we optimize response of resonant by varying geometry and material. The silicon nitride aluminum microstrings was measured. relative change in frequency per −1.74±0.04%/°C is more than one order magnitude higher comparable state-of-the-art AuPd strings.
Generation of quantum resources like entanglement is pivotal for technology. This work uses superconducting Josephson metamaterials to generate color-entangled photons from vacuum fluctuations at a high rate, showing the presented system be superb microwave generator with remarkable bandwidth. Successful squeezing light also demonstrated. These results are quite promising computing, sensing, and communication devices.
We demonstrate that a suspended metal wire array can be used to produce high-pressure sound waves over wide spectrum using the thermoacoustic effect. fabricated air-bridge arrays containing up 2×105 wires covering an area of few square centimeters. The supporting silicon wafer was isotropically plasma etched release thereby avoiding heat contact with substrate. Sound pressure levels reaching 110 dB at distance 8 cm were demonstrated near 40 kHz in free field. devices are also able reproduce...
We demonstrate the narrow switching distribution of an underdamped Josephson junction from zero to finite voltage state at millikelvin temperatures. argue that such junctions can be used as ultrasensitive detectors single photons in GHz range, operating close quantum limit: a given initial (zero voltage) driven by incoming signal state. The width nominal temperature about T = 10 mK was 4.5 nA, which corresponds effective noise device below 60 mK.
The existence of vacuum fluctuations is one the most important predictions modern quantum field theory. In state, occurring at different frequencies are uncorrelated. However, if a parameter in Lagrangian modulated by an external pump, stimulate spontaneous downconversion processes, creating squeezing between modes symmetric with respect to half frequency pump. Here we show that double parametric pumping superconducting microwave cavity, it possible generate another fundamental type...
Superconducting qubits are one of the most promising candidates to implement quantum computers. The superiority superconducting computers over any classical device in simulating random but well-determined circuits has already been shown two independent experiments and important steps have taken error correction. However, currently wide-spread qubit designs do not yet provide high enough performance enable practical applications or efficient scaling logical owing several following issues:...
We present a cryogenic microwave noise source with characteristic impedance of 50 Ω, which can be installed in coaxial line cryostat. The bath temperature the is continuously variable between 0.1 K and 5 without causing significant back-action heating on sample space. As proof-of-concept experiment, we perform Y-factor measurements an amplifier cascade that includes traveling wave parametric commercial high electron mobility transistor amplifier. observe system temperatures as low 680−200+20...
We theoretically propose and experimentally implement a method of measuring qubit by driving it close to the frequency dispersively coupled bosonic mode. The separation states corresponding different begins essentially immediately at maximum rate, leading speedup in measurement protocol. Also mode can be simultaneously driven optimize speed fidelity. test this protocol using superconducting resonator For certain time, we observe that conventional dispersive readout yields 100% higher average...
We fabricate and characterize superconducting through-silicon vias electrodes suitable for quantum processors. measure internal quality factors of a million test resonators excited at single-photon levels, on chips with used to stitch ground planes the front back sides chips. This resonator performance is par state art silicon-based planar solutions, despite presence vias. Via stitching an important enabling technology increasing physical size processor chips, first step toward more complex...
We used the band structure of a mesoscopic Josephson junction to construct low-noise amplifiers. By taking advantage quantum dynamics junction, i.e., interplay interlevel transitions and Coulomb blockade Cooper pairs, we created transistor-like devices, Bloch oscillating transistors, with considerable current gain high-input impedance. In these correlated supercurrent pairs is controlled by small base made up single electrons. Our devices reached power gains on order 30 5, respectively. The...
We present thermal detectors based on 40 nm-thick strain tuned single crystalline silicon membranes shaped into a heater area supported by narrow n- and p-doped beams, which also operate as thermocouple. The electro-thermal characterization of the devices reveals noise equivalent power 13 pW/Hz1/2 time constant 2.5 ms. high sensitivity is due to Seebeck coefficient 0.39 mV/K reduction conductivity Si beams from bulk value. performance enables fast sensitive detection low levels infrared...
Superconducting microwave circuits show great potential for practical quantum technological applications such as information processing. However, fast and on-demand initialization of the degrees freedom in these devices remains a challenge. Here, we experimentally implement tunable heat sink that is potentially suitable superconducting qubits. Our device consists two coupled resonators. The first resonator has high quality factor fixed frequency whereas second designed to have low resonance...
Abstract Since the introduction of bolometers more than a century ago, they have been used in various applications ranging from chemical sensors, consumer electronics, and security to particle physics astronomy. However, faster with lower noise are great interest fundamental point view find new use-cases for this versatile concept. We demonstrate nanobolometer that exhibits roughly an order magnitude equivalent power, $$20\,{\mathrm{zW}}/\sqrt {{\mathrm{Hz}}}$$ <mml:math...
Flux trapping and random flux movement are common problems in superconducting thin-film devices. Ultrasensitive magnetic field sensors based on quantum interference devices (SQUIDs) coupled to large pickup coils especially vulnerable strong external fields. The issue has become particularly relevant with the introduction of SQUID-based ultra-low-field (ULF) nuclear resonance (NMR) imaging (MRI) techniques. In this paper, we study constraints thin-film-based magnetometers gradiometers as...
We present a structure and fabrication method for superconducting tunnel junctions down to the dimensions of 200 nm using i-line UV lithography. The key element is side-wall-passivating spacer (SWAPS) which shaped smooth crossline contacting low parasitic capacitance. SWAPS enables formation with at or below lithography-limited linewidth. An additional benefit avoiding excessive use amorphous dielectric materials favorable in sub-Kelvin microwave applications often plagued by nonlinear lossy...
Sub-THz imaging techniques are currently emerging with applications especially in security screening requiring higher throughput mass transit and public areas. In the context of person imagers, field view spatial resolution set requirement for number image pixels. We perform an experimental feasibility study on a fully staring radiometric camera one detector per pixel. The aim is to avoid shortcomings characteristic optomechanical scanners limited detectors. Our approach based...
We introduce a microwave submillimeter-wave detector based on an integrated micromesh absorber and superconducting kinetic inductance thermometer through-wafer released sub-micron thick membrane. Equilibrium operation achieved by thermal isolation through the membrane geometry enables at elevated bath temperatures of 5–10 K. The bolometer operates in phonon-noise limited regime with measured noise equivalent temperature difference below 10 mK 1 s integration time, which is sufficient for...