arXiv subjects

Erik Szakiel

Publications and source records attributed to Erik Szakiel.

5 recordsLinked to original sources

arXiv2026

Millisecond phonon lifetimes in piezoelectric nanomechanical resonators

Piezoelectric nanomechanical resonators operating at gigahertz frequencies are a promising platform for quantum information processing and precision sensing, but phonon lifetimes have been limited to the microsecond range, widely attributed to the higher intrinsic loss of piezoelectric materials. Here we show that this limitation is not fundamental. Using a fabrication process informed by recent studies of defect-mediated loss in lithium niobate, we combine chemical restoration of ion-milled surfaces with a shadow-mask metallization process to produce lithium niobate phononic crystal resonators with inferred internal phonon lifetimes of up to 21 milliseconds at 3.6 gigahertz, corresponding to quality factors exceeding $4\times10^8$ ($f\cdot Q_i > 10^{18}$) at millikelvin temperatures. By systematically varying the electrode-to-resonator spacing, we demonstrate that the measured lifetime is set by external coupling between the device and the measurement circuit rather than material loss. This establishes that lithium niobate, once fabrication-induced surface damage is removed, achieves an intrinsic quality comparable to the best mechanical materials while remaining an intrinsically piezoelectric platform with strong electromechanical coupling.

cond-mat.mes-hall↗

arXiv2026

Quantum jumps of sound

Quantum mechanics predicts that a vibrating object's energy comes in discrete packets, yet no measurement of its position reveals this discreteness. Resolving individual energy levels requires a qualitatively different measurement, one coupling to the resonator's energy rather than its displacement. We use a superconducting qubit dispersively coupled to a nanomechanical resonator to perform repeated quantum nondemolition measurements of the phonon number. An aligned transfer-print technique integrating the qubit and resonator yields a mechanical lifetime of $T_1 = 2.1$ milliseconds and a dispersive shift of $2χ/2π= 328$ kilohertz per phonon. We heralded single-phonon states with 85% fidelity and observed quantum jumps between the resonator's first excited state and ground state. These discontinuous transitions are a striking manifestation of quantum mechanics in a massive, vibrating object.

quant-ph↗

arXiv2025

Robotic chip-scale nanofabrication for superior consistency

Unlike the rigid, high-volume automation found in industry, academic research requires process flexibility that has historically relied on variable manual operations. This hinders the fabrication of advanced, complex devices. We propose to address this gap by automating these low-volume, high-stakes tasks using a robotic arm to improve process control and consistency. As a proof of concept, we deploy this system for the resist development of Josephson junction devices. A statistical comparison of the process repeatability shows the robotic process achieves a resistance spread across chips close to 2%, a significant improvement over the ~7% spread observed from human operators, validating robotics as a solution to eliminate operator-dependent variability and a path towards industrial-level consistency in a research setting.

physics.app-ph↗

arXiv2025

Surface and Bulk Two-Level System Losses in Lithium Niobate Acoustic Resonators

Lithium niobate (LN) is a promising material for building acoustic resonators used in quantum applications, but its performance is limited by poorly understood material defects called two-level systems (TLS). In this work, we fabricate high-performance acoustic resonators from LN with quality factors up to $6\times10^7$ and use them to separate bulk and surface contributions to TLS loss. By comparing these bulk acoustic wave (BAW) resonators with previous surface acoustic wave and phononic crystal studies, we show that devices with high surface participation ratios are limited by surface TLS, while our BAW devices reveal an intrinsic bulk TLS limit. Through systematic surface treatments and microscopy, we demonstrate that BAW resonator performance remains unchanged despite surface modifications, confirming operation in a bulk-limited regime. Our work establishes quantitative bounds on both surface and bulk TLS losses in LN, within the context of material growth and fabrication approaches we have pursued, and provides guidance for future device engineering and materials development.

cond-mat.mes-hall↗

arXiv2022

CCAT-prime: RFSoC Based Readout for Frequency Multiplexed Kinetic Inductance Detectors

The Prime-Cam instrument on the Fred Young Submillimeter Telescope (FYST) is expected to be the largest deployment of millimeter and submillimeter sensitive kinetic inductance detectors to date. To read out these arrays efficiently, a microwave frequency multiplexed readout has been designed to run on the Xilinx Radio Frequency System on a Chip (RFSoC). The RFSoC has dramatically improved every category of size, weight, power, cost, and bandwidth over the previous generation readout systems. We describe a baseline firmware design which can read out four independent RF networks each with 500 MHz of bandwidth and 1000 detectors for ~30 W. The overall readout architecture is a combination of hardware, gateware/firmware, software, and network design. The requirements of the readout are driven by the 850 GHz instrument module of the 7-module Prime-Cam instrument. These requirements along with other constraints which have led to critical design choices are highlighted. Preliminary measurements of the system phase noise and dynamic range are presented.

astro-ph.IM↗