Ivan Nekrashevich

Sapphire Substrate Trenching to Advance Superconducting High-Coherence Quantum Devices

Sabrina Garattoni, Northwestern U., Mustafa Bal, Francesco Crisa et autres

Achieving longer coherence times in superconducting qubits is essential for advancing quantum information processing and enabling scalable quantum computing. This work presents an innovative fabrication strategy focused on sapphire trenching of the substrate of superconducting high-coherence quantum devices, developed by the SQMS …

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A Dark Photon Dark Matter Search with a Widely-Tunable SRF Cavity

Raphael Cervantes, Bianca Giaccone, Oleksandr Melnychuk, Sergey Viktorovich Kazakov et autres

The SERAPH (SupERconducting Axion and Paraphoton Haloscope) experiment is a family of superconducting haloscopes being developed by the Superconducting Quantum Materials and Systems (SQMS) Center to search for wavelike dark matter. This presentation will focus on preliminary results from our dark photon …

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A Dark Photon Dark Matter Search with a Widely-Tunable SRF Cavity

Raphael Cervantes, Bianca Giaccone, Oleksandr Melnychuk, Sergey Kazakov et autres

The SERAPH (SupERconducting Axion and Paraphoton Haloscope) experiment is a family of superconducting haloscopes being developed by the Superconducting Quantum Materials and Systems (SQMS) Center to search for wavelike dark matter. This presentation will focus on preliminary results from our dark photon …

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Strategies for Superconducting Transmon Qubits with Millisecond T$_1$ Relaxation Time

Mustafa Bal, Akshay A. Murthy, Francesco Crisa, Sabrina Garattoni et autres

Significant strides have been made in extending qubit lifetimes by mitigating lossy materials at various surfaces and interfaces of superconducting transmon qubits. We have recently demonstrated a five-fold improvement of T1 energy relaxation time by encapsulating the Nb surface to prevent native …

SQMS Nanofabrication Taskforce: Towards Fabrication of High Coherence Superconducting Qubits

Mustafa Bal, Francesco Crisa, Akshay A. Murthy, Shaojiang Zhu et autres

SQMS Nanofabrication Taskforce, which brings together experts in nanofabrication and materials science at the SQMS Center, has been launched to implement novel materials, substrates, and fabrication techniques for high coherence superconducting quantum devices. In a first coordinated effort, the Nanofabrication Taskforce developed …

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Systematic improvements in transmon qubit coherence enabled by niobium surface encapsulation

Mustafa Bal, Akshay A. Murthy, Shaojiang Zhu, Francesco Crisa et autres

Abstract We present a transmon qubit fabrication technique that yields systematic improvements in T 1 relaxation times. We encapsulate the surface of niobium and prevent the formation of its lossy surface oxide. By maintaining the same superconducting metal and only varying the …

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Two-Tone Spectroscopy of 3D SRF Cavities to Understand Two-Level System Loss

Bianca Giaccone, A. Netepenko, Roman Pilipenko, D. Frolov et autres

So-called two-level system (TLS) defects are among the most detrimental sources of loss and decoherence in superconducting quantum devices, and their microscopic nature still poorly understood. We develop a two-tone spectroscopy technique to characterize the spectral line width of TLS. This knowledge …

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Systematic Improvements in Transmon Qubit Coherence Enabled by Niobium Surface Encapsulation

Mustafa Bal, Akshay A. Murthy, Shaojiang Zhu, Francesco Crisa et autres

We present a novel transmon qubit fabrication technique that yields systematic improvements in T$_1$ relaxation times. We fabricate devices using an encapsulation strategy that involves passivating the surface of niobium and thereby preventing the formation of its lossy surface oxide. By maintaining …

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Coupled surface plasmon–phonon polariton nanocavity arrays for enhanced mid‐infrared absorption

Satya R. Kachiraju, Ivan Nekrashevich, Imtiaz Ahmad, Hira Farooq et autres

Abstract Resonant optical cavities are essential components in mid‐infrared applications. However, typical film‐type cavities require multilayer stacks with a micron‐thick spacer due to mid‐infrared wavelengths, and their performance is limited by narrow frequency tunability and angular sensitivity. We propose and experimentally demonstrate …

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Methods for microwave characterization of electro-optic crystals for quantum transduction

Silvia Zorzetti, Changqing Wang, I. Gonin, S. Kazakov et autres

Microwave-optic quantum transducers are essential devices to develop distributed quantum networks and implement related quantum communication protocols. Three dimensional high-coherence time microwave cavities embedded with electro-optic nonlinear dielectric materials provide promising platforms to boost the efficiency of the microwave-optic frequency conversion. However, …

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Quantum computing hardware for HEP algorithms and sensing

M. Sohaib Alam, Sergey A. Belomestnykh, Nicholas Bornman, Gustavo I. Cancelo et autres

Quantum information science harnesses the principles of quantum mechanics to realize computational algorithms with complexities vastly intractable by current computer platforms. Typical applications range from quantum chemistry to optimization problems and also include simulations for high energy physics. The recent maturing of …

Reaching the equilibrium state of the frustrated triangular Ising magnet Ca3Co2O6

Ivan Nekrashevich, X. X. Ding, Fedor Balakirev, Hee Taek Yi et autres

Ca${}_{3}$Co${}_{2}$O${}_{6}$ is a triangular frustrated Ising magnet whose magnetic properties have puzzled the community for decades and have generated many theoretical descriptions. The magnetization shows regular steps with magnetic field that are metastable for days to weeks at low temperatures. Here, the …

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