Roman Pilipenko

Bio: Roman Pilipenko is an academic researcher from Fermilab. The author has contributed to research in topics: Physics & Superconducting magnet. The author has an hindex of 5, co-authored 15 publications receiving 139 citations.

Three-Dimensional Superconducting Resonators at T <20 mK with Photon Lifetimes up to τ =2 s

Abstract: Very-high-quality-factor superconducting radio-frequency cavities developed for accelerators can enable fundamental physics searches with orders of magnitude higher sensitivity, and they can also offer a path to a 1000-fold increase in the achievable coherence times for cavity-stored quantum states in three-dimensional circuit QED architecture. Here we report measurements of multiple accelerator cavities of resonant frequencies of ${f}_{0}=1.3$, 2.6, 5 GHz down to temperatures of about 10 mK and field levels down to a few photons, which reveal very long photon lifetimes up to 2 s, while also further exposing the role of the two-level systems (TLS) in niobium oxide. We also demonstrate how the TLS contribution can be greatly suppressed by vacuum heat treatments at 340--450 ${}^{\ensuremath{\circ}}\mathrm{C}$.

Three-dimensional superconducting resonators at $T < 20$ mK with the photon lifetime up to $\tau=2$ seconds

Abstract: Very high quality factor superconducting radio frequency cavities developed for accelerators can enable fundamental physics searches with orders of magnitude higher sensitivity, as well as offer a path to a 1000-fold increase in the achievable coherence times for cavity-stored quantum states in the 3D circuit QED architecture. Here we report the first measurements of multiple accelerator cavities of $f_0=$1.3, 2.6, 5 GHz resonant frequencies down to temperatures of about 10~mK and field levels down to a few photons, which reveal record high photon lifetimes up to 2 seconds, while also further exposing the role of the two level systems (TLS) in the niobium oxide. We also demonstrate how the TLS contribution can be greatly suppressed by the vacuum heat treatments at 340-450$^\circ$C.

Searches for New Particles, Dark Matter, and Gravitational Waves with SRF Cavities

Abstract: Asher Berlin, 1 Sergey Belomestnykh, 3, 4 Diego Blas, 6 Daniil Frolov, Anthony J. Brady, 1 Caterina Braggio, 9, 1 Marcela Carena, 10, 1 Raphael Cervantes, Mattia Checchin, Crispin Contreras-Martinez, 3 Raffaele Tito D’Agnolo, Sebastian A. R. Ellis, Grigory Eremeev, 3 Christina Gao, 2, 1 Bianca Giaccone, Anna Grassellino, 3 Roni Harnik, 2, ∗ Matthew Hollister, 3 Ryan Janish, 1 Yonatan Kahn, 1 Sergey Kazakov, 3 Doga Murat Kurkcuoglu, 1 Zhen Liu, 1 Andrei Lunin, Alexander Netepenko, 3 Oleksandr Melnychuk, Roman Pilipenko, 3 Yuriy Pischalnikov, 3 Sam Posen, 3, † Alex Romanenko, 3 Jan Schütte-Engel, 1 Changqing Wang, Vyacheslav Yakovlev, 3 Kevin Zhou, Silvia Zorzetti, and Quntao Zhuang 1, 17 Superconducting Quantum Materials and Systems Center (SQMS), Fermi National Accelerator Laboratory, Batavia, IL 60510, USA Theory Division, Fermi National Accelerator Laboratory, Batavia, IL 60510, USA Applied Physics and Superconducting Technology Division, Fermi National Accelerator Laboratory, Batavia, IL 60510, USA Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794, USA Grup de F́ısica Teòrica, Departament de F́ısica, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain Institut de Fisica d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra (Barcelona), Spain Department of Electrical and Computer Engineering, University of Arizona, Tucson, Arizona 85721, USA Dipartimento di Fisica e Astronomia, Padova, Italy INFN, Sezione di Padova, Padova, Italy Department of Physics, University of Chicago, Chicago, Illinois, 60637, USA Université Paris Saclay, CEA, CNRS, Institut de Physique Théorique, 91191, Gif-sur-Yvette, France Département de Physique Théorique, Université de Genève, 24 quai Ernest Ansermet, 1211 Genève 4, Switzerland Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA Fermilab Quantum Institute, Fermi National Accelerator Laboratory, Batavia, IL 60510, USA School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA J. C. Wyant College of Optical Sciences, University of Arizona, Tucson, Arizona 85721, USA (Dated: March 25, 2022)

Mu2e Transport Solenoid Prototype Tests Results

Abstract: The Fermilab Mu2e experiment has been developed to search for evidence of charged lepton flavor violation through the direct conversion of muons into electrons. The transport solenoid is an s-shaped magnet that guides the muons from the source to the stopping target. It consists of 52 superconducting coils arranged in 27 coil modules. A full-size prototype coil module, with all the features of a typical module of the full assembly, was successfully manufactured by a collaboration between INFN-Genoa and Fermilab. The prototype contains two coils that can be powered independently. To validate the design, the magnet went through an extensive test campaign. Warm tests included magnetic measurements with a vibrating stretched wire and electrical and dimensional checks. The cold performance was evaluated by a series of power tests and temperature dependence and minimum quench energy studies.

An FPGA-Based Quench Detection and Continuous Logging System for Testing Superconducting Magnets

Abstract: A quench detection system for testing superconducting magnets with two concurrent data logging modes was developed at Fermilab. This system consists of two functional components: An active quench detection component, which is based on a reconfigurable input/output module with a field-programmable gate array, and a data logger component based on a set of simultaneous sampling data logger modules. The data logger component has two concurrent modes of operation: A fast logger mode that is triggered to capture a user specified window of data at rates up to 10 kHz, and a continuous data logger mode that can log data at rates between 0.1 and 100 Hz continuously using the same data loggers. The system was designed with a modular structure using commercially available hardware along with in-house developed programmable isolation amplifiers. This approach makes the new system easily scalable for multiple magnets or magnets with more complex coil and lead voltage tap configurations. The new system has been used for testing the MICE Spectrometer Solenoid. A detailed description of the system along with test results is presented in this paper.

Circuit quantum electrodynamics

Abstract: Quantum-mechanical effects at the macroscopic level were first explored in Josephson-junction-based superconducting circuits in the 1980s. In recent decades, the emergence of quantum information science has intensified research toward using these circuits as qubits in quantum information processors. The realization that superconducting qubits can be made to strongly and controllably interact with microwave photons, the quantized electromagnetic fields stored in superconducting circuits, led to the creation of the field of circuit quantum electrodynamics (QED), the topic of this review. While atomic cavity QED inspired many of the early developments of circuit QED, the latter has now become an independent and thriving field of research in its own right. Circuit QED allows the study and control of light-matter interaction at the quantum level in unprecedented detail. It also plays an essential role in all current approaches to gate-based digital quantum information processing with superconducting circuits. In addition, circuit QED provides a framework for the study of hybrid quantum systems, such as quantum dots, magnons, Rydberg atoms, surface acoustic waves, and mechanical systems interacting with microwave photons. Here the coherent coupling of superconducting qubits to microwave photons in high-quality oscillators focusing on the physics of the Jaynes-Cummings model, its dispersive limit, and the different regimes of light-matter interaction in this system are reviewed. Also discussed is coupling of superconducting circuits to their environment, which is necessary for coherent control and measurements in circuit QED, but which also invariably leads to decoherence. Dispersive qubit readout, a central ingredient in almost all circuit QED experiments, is also described. Following an introduction to these fundamental concepts that are at the heart of circuit QED, important use cases of these ideas in quantum information processing and in quantum optics are discussed. Circuit QED realizes a broad set of concepts that open up new possibilities for the study of quantum physics at the macro scale with superconducting circuits and applications to quantum information science in the widest sense.

Materials loss measurements using superconducting microwave resonators.

Abstract: The performance of superconducting circuits for quantum computing is limited by materials losses. In particular, coherence times are typically bounded by two-level system (TLS) losses at single photon powers and millikelvin temperatures. The identification of low loss fabrication techniques, materials, and thin film dielectrics is critical to achieving scalable architectures for superconducting quantum computing. Superconducting microwave resonators provide a convenient qubit proxy for assessing performance and studying TLS loss and other mechanisms relevant to superconducting circuits such as non-equilibrium quasiparticles and magnetic flux vortices. In this review article, we provide an overview of considerations for designing accurate resonator experiments to characterize loss, including applicable types of losses, cryogenic setup, device design, and methods for extracting material and interface losses, summarizing techniques that have been evolving for over two decades. Results from measurements of a wide variety of materials and processes are also summarized. Finally, we present recommendations for the reporting of loss data from superconducting microwave resonators to facilitate materials comparisons across the field.

Efficient Multiphoton Sampling of Molecular Vibronic Spectra on a Superconducting Bosonic Processor

Abstract: A quantum simulator uses microwave photons to tackle a useful chemistry problem---determining the vibronic spectra of molecules.

Detection of early-universe gravitational-wave signatures and fundamental physics

Abstract: Abstract Detection of a gravitational-wave signal of non-astrophysical origin would be a landmark discovery, potentially providing a significant clue to some of our most basic, big-picture scientific questions about the Universe. In this white paper, we survey the leading early-Universe mechanisms that may produce a detectable signal—including inflation, phase transitions, topological defects, as well as primordial black holes—and highlight the connections to fundamental physics. We review the complementarity with collider searches for new physics, and multimessenger probes of the large-scale structure of the Universe.

Engineering high-coherence superconducting qubits

Abstract: Advances in materials science and engineering have played a central role in the development of classical computers and will undoubtedly be critical in propelling the maturation of quantum information technologies. In approaches to quantum computation based on superconducting circuits, as one goes from bulk materials to functional devices, amorphous films and non-equilibrium excitations — electronic and phononic — are introduced, leading to dissipation and fluctuations that limit the computational power of state-of-the-art qubits and processors. In this Review, the major sources of decoherence in superconducting qubits are identified through an exploration of seminal qubit and resonator experiments. The proposed microscopic mechanisms associated with these imperfections are summarized, and directions for future research are discussed. The trade-offs between simple qubit primitives based on a single Josephson tunnel junction and more complex designs that use additional circuit elements, or new junction modalities, to reduce sensitivity to local noise sources are discussed, particularly in the context of materials optimization strategies for each architecture. Superconducting qubits hold great promise for quantum computing, and recently there have been dramatic improvements in both coherence times and the power of quantum processors. This Review explores how the path forward involves balancing circuit complexity and materials perfection, eliminating defects while designing qubits with engineered noise resilience.