A5107169111- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Magnetic properties of thin films
- Quantum Information and Cryptography
- Superconducting and THz Device Technology
- Mechanical and Optical Resonators
- Theoretical and Computational Physics
- Quantum Computing Algorithms and Architecture
- Magnetic and transport properties of perovskites and related materials
- Multiferroics and related materials
- Metamaterials and Metasurfaces Applications
- Ferroelectric and Piezoelectric Materials
- Magneto-Optical Properties and Applications
- Topological Materials and Phenomena
- Nuclear Materials and Properties
- Quantum Electrodynamics and Casimir Effect
- Iron-based superconductors research
- Strong Light-Matter Interactions
- Rare-earth and actinide compounds
- Thermal Radiation and Cooling Technologies
- Advanced Condensed Matter Physics
- Advanced Materials Characterization Techniques
- Advanced Frequency and Time Standards
- Quantum many-body systems
- Atomic and Subatomic Physics Research
National University of Science and Technology
2015-2024
Russian Quantum Center
2021-2023
Michigan Science Center
2015
Superconducting fluxonium qubits provide a promising alternative to transmons on the path toward large-scale superconductor-based quantum computing due their better coherence and larger anharmonicity. A major challenge for multi-qubit devices is experimental demonstration of scalable crosstalk-free architecture with high fidelity single-qubit two-qubit gates, single-shot readout state initialization. Here, we present fluxonium-based processor tunable coupler element following our theoretical...
The ultrastrong photon-to-magnon coupling is reached with an on-chip hybrid system using superconducting phenomena.
Scalable quantum computers hold the promise to solve hard computational problems, such as prime factorization, combinatorial optimization, simulation of many-body physics, and chemistry. While being key understanding many real-world phenomena, nonconservative dynamics presents a challenge for unitary computation. In this work, we focus on simulating nonunitary parity-time-symmetric systems, which exhibit distinctive symmetry-breaking phase transition well other unique features that have no...
Abstract In this work, a new hybridization of superconducting and ferromagnetic orders is demonstrated, promising for magnonics. By measuring the spin wave resonance absorption spectra magnetostatically coupled permalloy/niobium bilayer at different temperatures, magnetostatic resonances with unconventional dispersion are observed. The mechanism behind modified dispersion, confirmed micromagnetic simulations, implies screening alternating stray fields precessing magnetic moments in layer by...
In this work, magnetization dynamics is studied in superconductor/ferromagnet/superconductor three-layered films a wide frequency, field, and temperature ranges using the broad-band ferromagnetic resonance measurement technique. It shown that presence of both superconducting layers proximity at superconductor/ferromagnet interfaces massive shift to higher frequencies emerges. The phenomenon robust essentially long-range: it has been observed for set samples with thickness layer range from...
In this work, the ultra-strong photon-to-magnon coupling is demonstrated for on-chip multilayered superconductor/ferromagnet/insulator hybrid thin film structures reaching strength above 6 GHz, ratio about 0.6, single-spin 350 Hz, and cooperativity 10^4. High characteristics of are achieved owing to a radical suppression photon phase velocity in electromagnetic resonator. With spectrum reveals inapplicability Dicke model, evidences contribution diamagnetic A^2 interaction term Hamiltonian...
Topological photonics enables resilient routing and localization of light. Of special interest are topological states quantum light promising disorder-robust correlations. Here, the authors design fabricate a one-dimensional dimerized array superconducting qubits. Performing microwave spectroscopy this fabricated metamaterial, they observe not only single-photon but also bands exotic bound photon pairs mediated by anharmonicity They discuss two-photon edge-localized state analyze robustness...
In this work, we study magnetization dynamics in superconductor-ferromagnet-superconductor thin-film structures. Results of the broad-band ferromagnetic resonance spectroscopy are reported for a large set samples with varied thickness both superconducting and layers wide frequency, field, temperature ranges. Experimentally one-dimensional anisotropic action torque on is established; its dependence revealed. It demonstrated that experimental findings support recently proposed mechanism...
In this work, a class of metamaterials is proposed on the basis ferromagnet/superconductor hybridization for applications in magnonics. These comprise ferromagnetic magnon medium that coupled inductively to superconducting periodic microstructure. Spectroscopy magnetization dynamics such hybrid evidences formation areas with alternating dispersions spin wave propagation, which basic requirement development known as magnonic crystals. The spectrum allows derivation impact structure...
Motivated by recent burst of applications ferromagnetic layers in superconducting digital and quantum elements, we study the magnetism thin films patterned microstructures Pd0.99Fe0.01. In this diluted system, a high-sensitivity resonance (FMR) experiment reveals spectroscopic signatures re-magnetization enables estimation saturation magnetization, anisotropy field, Gilbert damping constant. The detailed analysis FMR spectra links observed unexpectedly high reduced field (0.06–0.14) with...
In this work we propose and explore an effective numerical approach for investigation of critical current dependence on applied magnetic field Josephson junctions with in-plane magnetization orientation. This is based micromagnetic simulation the reversal process in ferromagnetic layer introduced internal stiffness subsequent reconstruction value using total flux or reconstructed actual phase difference distribution. The flexible shows good agreement experimental data obtained barriers....
In this work, we consider dispersion laws of spin waves that propagate in a ferromagnet/superconductor bilayer, specifically ferromagnetic film coupled inductively to superconductor. The coupling is viewed as an interaction wave with its mirrored image generated by the We show that, general, enhances substantially phase velocity magnons in-plane geometries. addition, heavy nonreciprocity law observed magnetostatic surface geometry where depends on direction propagation.
This work is focused on the numerical investigation of spin waves that propagate in nonlinear ferromagnet/superconductor bilayered films and periodic structures. The nonlinearity these hybrid structures emerges due to non-monotonous dependence magnetization a superconducting subsystem magnetic field, which characterized by critical field. It shown at relatively high amplitudes comparison spin-wave spectrum changes drastically: spectral line can either bifurcate or stretch continuously...
We report investigation of ferromagnetic resonance phenomenon in thin films with essentially non-uniform composition. Epitaxial Pd-Fe film linear distribution Fe content across the thickness is used as model material. Anomalous perpendicular standing spin waves are observed and quantified using collective dynamic equation. Numerical analysis yields exchange stiffness constant for diluted alloy $D=2A/\mu_0M_s=15$~T$\cdot$nm$^2$ ratio effective magnetization to saturation $M_{eff}/M_s=1.16$....
Tunable couplers have recently become one of the most powerful tools for implementing two-qubit gates between superconducting qubits. A tunable coupler typically includes a nonlinear element, such as quantum interference device, which is used to tune resonance frequency an LC circuit connecting two Here we propose complimentary approach where instead tuning by applying quasistatic control signal, excite microwave degree freedom associated with itself. Because strong effective longitudinal...
In this work we propose a hybrid device based on long Josephson junction (JJ) coupled inductively to an external ferromagnetic (FM) layer. The JJ in zero-field operation mode induces localized AC magnetic field the FM layer and enables synchronized magnetostatic standing wave. wave additional dissipation for soliton propagation also phase locking (resonant synchronization) at frequency of natural resonance. later manifests itself as constant voltage step current–voltage characteristics...
We present a theoretical and experimental study of electrodynamics planar spiral superconducting resonator finite length. The is made in the form monofilar Archimedean spiral. By making use general model inhomogeneous alternating current flowing along specific boundary conditions on surface strip, we obtain analytically frequencies fn resonances which can be excited such system. also calculate corresponding RF distributions ψn(r), where r coordinate across show that resonant are well...
Magnonics, conventionally a room-temperature discipline, develops exceptional features when operated at cryogenic temperatures. The related low-temperature magnetization dynamics and their interplay with superconductors is of increasing interest for various avenues in data processing. This investigation magnonics reports the single-crystalline ultrathin film yttrium iron garnet superconducting planar waveguide on top. magnetic anisotropies shaped by metal structures, drastically increased...
The specific heat cp and magnetization of single crystal hexagonal manganites the type Yb1−xCaxMnO3 (x = 0, 0.05, 0.10) were measured in a wide temperature range as function magnetic field. Antiferromagnetic ordering Mn sublattice occurs at TN 83 K. Ca doping has surprisingly minimal effect on properties. At low (∼3.5 K), all compounds show ferromagnetic (FM) basal plane attributed to Yb site 2a. For fields applied along c direction, spin reorientation FM disappears. shows broad maximum...
In this work, we propose and explore a sensitive technique for investigation of ferromagnetic resonance corresponding magnetic properties individual micro-scaled and/or weak samples. The is based on coupling the investigated sample to high-Q transmission line superconducting resonator, where response studied at eigen frequencies resonator. high quality factor resonator enables detection absorption losses multiple resonance. Studying microwave permalloy rectangles, have confirmed superiority...
In this paper, we report the results of magnetic resonance spectroscopy ${\mathrm{EuFe}}_{2}{\mathrm{As}}_{2}$ single crystals. We observe responses, which are attributed to antiferromagnetic resonances Eu sublattice with orthorhombic crystal structure and different orientations twin domains relative external field. confirm validity recently proposed spin Hamiltonian anisotropic Eu-Eu exchange interaction biquadratic Eu-Fe interaction.
We present a practical design and implementation of broadband sample holder suitable for microwave experiments with superconducting integrated circuits at millikelvin temperatures. Proposed can be easily in standard dilution cryostats, has flat pass band response frequency range from 0 to 32 GHz, allowing the RF testing samples substrate size up 4x4 mm. The parasitic higher modes interference structure is analyzed prevented via considerations. developed setup used characterization parametric...
To improve both scalability and noise-filtering capability of a transition-edge sensor (TES), new concept thin-film detector is suggested, which based on embedding microbridge TES into high-Q planar GHz-range resonator weakly coupled to 50-Ω-readout transmission line. Such element designed as hot-electron microbolometer THz-range antenna load the at same time. A weak THz signal heats TES, thus reducing quality factor leading power increment in readout The power-to-power conversion gain, an...