arXiv subjects

Emilio A. Nanni

Publications and source records attributed to Emilio A. Nanni.

At least 19 recordsLinked to original sources

arXiv2026

Non-Linear Dynamics Induced by Strong Radio-Frequency Fields in ReBCO High Temperature Superconductors

Probing the dynamics of superconducting transitions induced by strong electromagnetic fields is vital to designing high power devices leveraging these materials. The development of high temperature superconductors (HTS) is particularly interesting due to critical temperatures ($T_c$) approaching 90\,K, the ability to support high current densities, and their ability to operate in strong static magnetic fields. This work aims to determine the transition dynamics of these materials at radio-frequencies (rf) in the microwave range where they have enormous potential for new applications ranging from particle accelerators to dark matter searches. We have tested two types of coatings formed from rare earth barium copper oxide (REBCO): a film deposited by electron-beam physical vapor deposition, and HTS conductor tapes soldered to a copper substrate with exposed REBCO surfaces. Testing was performed via a hemispherical transverse-electric mode cavity that maximizes the surface rf magnetic field and minimizes the surface electric field on a 2-inch diameter sample. We report on steady-state measurements at low rf power, as well as fully time-resolved transition dynamics on the microsecond timescale seen for the first time with strong surface rf fields.

physics.acc-ph↗

arXiv2026

Perturbative sensing of nanoscale materials with millimeter-wave photonic crystals

We introduce millimeter-wave silicon photonic crystal cavities as a versatile platform for the perturbative sensing of nanoscale materials. This dielectric-based platform is compatible with strong magnetic fields, opening avenues for studying quantum materials in extreme environments where superconducting cavities cannot operate. To establish the platform's performance, we cryogenically characterize a silicon photonic crystal cavity at 4.3 K, achieving a total quality factor exceeding $10^5$ for a 96 GHz mode. As a proof-of-concept for its sensing capabilities, we position a hexagonal boron nitride-multilayer graphene (hBN-MLG) heterostructure at an electric-field antinode of the cavity and measure the perturbative response at room temperature. The heterostructure induces a significant change in the cavity's resonance, from which we extract a total sample conductivity of approximately $5.1\times10^6$~S/m. These results establish silicon photonic crystal cavities as a promising platform for sensitive, on-chip spectroscopy of nanoscale materials at millimeter-wave frequencies.

cond-mat.mes-hall↗

arXiv2026

Beam-Beam Backgrounds for the Cool Copper Collider

In this paper, we present a comprehensive characterization of beam-beam backgrounds for the Cool Copper Collider (C$^3$), a proposed linear $e^{+}e^{-}$ collider designed for precision Higgs studies at center-of-mass energies of 250 and 550 GeV. Using a simulation pipeline based on the Key4hep framework, we evaluate incoherent pair production and hadron photoproduction backgrounds through the SiD detector for baseline, power-efficiency, and high-luminosity C$^3$ operating scenarios. The occupancy induced by the beam-beam background is evaluated for each scenario, validating the compatibility of the existing SiD detector design with operations at C$^3$ without substantial modifications. At the same time, the modular simulation framework and analysis methodology presented in this paper offer a versatile toolkit for background studies in future collider proposals, contributing to a common platform for different machine designs.

hep-ex↗

arXiv2025

Optically accessible high-finesse millimeter-wave resonator for cavity quantum electrodynamics with atom arrays

Cavity quantum electrodynamics (QED) is a powerful tool in quantum science, enabling preparation of non-classical states of light and scalable entanglement of many atoms coupled to a single field mode. While the most coherent atom-photon interactions have been achieved using superconducting millimeter-wave cavities coupled to Rydberg atoms, these platforms so far lack the optical access required for trapping and addressing individual atomic qubits. We present a millimeter-wave Fabry-Pérot cavity with finesse $5.8(1) \times 10^7$ at a temperature of 1 K providing generous transverse optical access (numerical aperture 0.56). Conflicting goals of strong atom-photon coupling and optical access motivate a near-confocal geometry. Close to confocality, however, post-paraxial corrections to the cavity spectrum introduce unexpected degeneracies between transverse modes, leading to excess cavity loss. Modeling these corrections allows for tuning the cavity geometry to evade this loss, producing a high finesse that will enable cavity QED experiments with trapped atoms deep in the strong coupling regime.

quant-ph↗

arXiv2025

Three-dimensional reconstruction of THz near-fields from a LiNbO$_3$ optical rectification source

Terahertz (THz) generation by optical rectification in LiNbO$_3$ (LN) is a widely used technique for generating intense THz radiation. The spatiotemporal characterization of THz pulses from these sources is currently limited to far-field methods. While simulations of tilted pulse front THz generation have been published, little work has been done to measure the near-field properties of the THz source. A better understanding of the THz near-field properties will improve optimization of THz generation efficiency, transport, and coupling. We demonstrate a technique for quantitative spatiotemporal characterization of single-cycle strong-field THz pulses with 2D near-field electro-optic imaging. We have reconstructed the full temporal 3D THz near-field and shown how the phase front can be tailored by controlling the incident pump pulse.

physics.optics↗

arXiv2025

High Precision RF Pulse Shaping with Direct RF Sampling for Future Linear Accelerators

In various of particle accelerator designs, amplitude and phase modulation methods are commonly applied to shape the RF pulses for implementing pulse compressors or compensating for the fluctuations introduced by the high-power RF components and beam loading effects. Phase modulations are typically implemented with additional phase shifters that require drive or control electronics. With our recent next-generation LLRF (NG-LLRF) platform developed based on direct RF sampling technology of RF system-on-chip (RFSoC) devices, RF pulse shaping can be realized without the analogue phase shifters, which can significantly simplify the system architecture. We performed a range of high-power experiments in the C-band to evaluate the RF pulse-shaping capabilities of the NG-LLRF system at different stages of the RF circuits. In this paper, the high-power characterization results with the Cool Copper Collider (C3) structure driven by RF pulses with different modulation schemes will be described. With the pulse modulation and demodulation completely implemented in the digital domain, the RF pulse shaping schemes can be rapidly adapted for X-band structures simply by adding analogue mixers.

physics.acc-ph↗

arXiv2025

Next Generation LLRF Control and Monitoring System for S-Band Linear Accelerators

The low-level RF (LLRF) systems for S-band linear accelerating structures are typically implemented with heterodyne base architectures. We have developed and characterized the next generation LLRF (NG-LLRF) based on the RF system-on-chip (RFSoC) for C-band accelerating structures, and the platform delivered the pulse-to-pulse fluctuation levels considerably better than the requirement of the targeted applications. The NG-LLRF system uses the direct RF sampling technique of the RFSoC, which significantly simplified the architecture compared to the conventional LLRF. We have extended the frequency range of the NG-LLRF to S-band and experimented with different RFSoC devices and system designs to meet the more stringent requirements for S-band LLRF applications. In this paper, the characterization results of the platform with different system architectures will be summarized and the high-power test results of the NG-LLRF with the S-band accelerating structure in the Next Linear Collider Test Accelerator (NLCTA) test facility at the SLAC National Accelerator Laboratory will be presented and analyzed.

physics.acc-ph↗

arXiv2025

ESPPU INPUT: C$^3$ within the "Linear Collider Vision"

The Linear Collider Vision calls for a Linear Collider Facility with a physics reach from a Higgs Factory to the TeV-scale with $e^+e^{-}$ collisions. One of the technologies under consideration for the accelerator is a cold-copper distributed-coupling linac capable of achieving high gradient. This technology is being pursued by the C$^3$ collaboration to understand its applicability to future colliders and broader scientific applications. In this input we share the baseline parameters for a C$^3$ Higgs-factory and the energy reach of up to 3 TeV in the 33 km tunnel foreseen under the Linear Collider Vision. Recent results, near-term plans and future R\&D needs are highlighted.

physics.acc-ph↗

arXiv2025

Integrated sub-terahertz cavity electro-optic transduction

Emerging communications and computing technologies will rely ever-more on expanding the useful radio frequency (RF) spectrum into the sub-THz and THz frequency range. Both classical and quantum applications would benefit from advancing integration and incorporation of sub-THz and electro-optic technologies into common devices, such as modulators. Here we demonstrate an integrated triply-resonant, superconducting electro-optic transducer. Our design incorporates an on-chip $107$ GHz sub-THz niobium titanium nitride superconducting resonator, modulating a thin-film lithium niobate optical racetrack resonator operating at telecom wavelengths. We observe a maximum photon transduction efficiency of $η_{\text{OE}}\approx 0.82\times 10^{-6}$ and an average single-photon electro-optic interaction rate of $g_0/2π\approx 0.7$ kHz. We also present a study and analysis of the challenges associated with the design of integrated sub-THz resonators and propose possible solutions to these challenges. Our work paves the way for further advancements in resonant electro-optic technologies operating at sub-THz frequencies.

physics.optics↗

arXiv2024

Quantum limits of superconducting-photonic links and their extension to mm-waves

Photonic addressing of superconducting circuits has been proposed to overcome wiring complexity and heat load challenges, but superconducting-photonic links suffer from an efficiency-noise trade-off that limits scalability. This trade-off arises because increasing power conversion efficiency requires reducing optical power, which makes the converted signal susceptible to shot noise. We analyze this trade-off and find the infidelity of qubit gates driven by photonic signals scales inversely with the number of photons used, and therefore the power efficiency of the converter. While methods like nonlinear detection or squeezed light could mitigate this effect, we consider generating higher frequency electrical signals, such as millimeter-waves (100 GHz), using laser light. At these higher frequencies, circuits have higher operating temperatures and cooling power budgets. We demonstrate an optically-driven cryogenic millimeter-wave source with a power efficiency of $10^{-4}$ that can generate ${1}~\mathrm{μW}$ of RF power at 80 GHz with 1500 thermal photons of added noise at 4 K. Using this source, we perform frequency-domain spectroscopy of superconducting NbTiN resonators at 80-90 GHz. Our results show a promising approach to alleviate the efficiency-noise constraints on optically-driven superconducting circuits while leveraging the benefits of photonic signal delivery. Further optimization of power efficiency and noise at high frequencies could make photonic control of superconducting qubits viable at temperatures exceeding 1 kelvin.

quant-ph↗

arXiv2023

Utilization of Additive Manufacturing for the Rapid Prototyping of C-Band RF Loads

Additive manufacturing is a versatile technique that shows promise in providing quick and dynamic manufacturing for complex engineering problems. Research has been ongoing into the use of additive manufacturing for potential applications in radiofrequency (RF) component technologies. Here we present a method for developing an effective prototype load produced out of 316L stainless steel on a direct metal laser sintering machine. The model was tested within simulation software to verify the validity of the design. The load structure was manufactured utilizing an online digital manufacturing company, showing the viability of using easily accessible tools to manufacture RF structures. The produced load was able to produce an S$_{11}$ value of -22.8 dB at the C-band frequency of 5.712 GHz while under vacuum. In a high power test, the load was able to terminate a peak power of 8.1 MW. Discussion includes future applications of the present research and how it will help to improve the implementation of future accelerator concepts.

physics.acc-ph↗

arXiv2022

Report of the Snowmass 2021 e$^+$e$^-$-Collider Forum

A summary of the Snowmass 2021 e$^+$e$^-$-Collider Forum discussions, white papers submitted to the Snowmass 2021 community study, submissions of the Energy Frontier (EF) subgroups and the Accelerator Frontier (AF) Integrated Task Force (ITF) are presented.

hep-ex↗

arXiv2022

RF Accelerator Technology R&D: Report of AF7-rf Topical Group to Snowmass 2021

Accelerator radio frequency (RF) technology has been and remains critical for modern high energy physics (HEP) experiments based on particle accelerators. Tremendous progress in advancing this technology has been achieved over the past decade in several areas highlighted in this report. These achievements and new results expected from continued R&D efforts could pave the way for upgrades of existing facilities, improvements to accelerators already under construction (e.g., PIP-II), well-developed proposals (e.g., ILC, CLIC), and/or enable concepts under development, such as FCC-ee, CEPC, C3, HELEN, multi-MW Fermilab Proton Intensity Upgrade, future Muon Colloder, etc. Advances in RF technology have impact beyond HEP on accelerators built for nuclear physics, basic energy sciences, and other areas. Recent examples of such accelerators are European XFEL, LCLS-II and LCLS-II-HE, SHINE, SNS, ESS, FRIB, and EIC. To support and enable new accelerator-based applications and even make some of them feasible, we must continue addressing their challenges via a comprehensive RF R&D program that would advance the existing RF technologies and explore the nascent ones.

physics.acc-ph↗

arXiv2022

C$^3$ Demonstration Research and Development Plan

C$^3$ is an opportunity to realize an e$^+$e$^-$ collider for the study of the Higgs boson at $\sqrt{s} = 250$ GeV, with a well defined upgrade path to 550 GeV while staying on the same short facility footprint. C$^3$ is based on a fundamentally new approach to normal conducting linear accelerators that achieves both high gradient and high efficiency at relatively low cost. Given the advanced state of linear collider designs, the key system that requires technical maturation for C$^3$ is the main linac. This white paper presents the staged approach towards a facility to demonstrate C$^3$ technology with both Direct (source and main linac) and Parallel (beam delivery, damping ring, ancillary component) R&D. The white paper also includes discussion on the approach for technology industrialization, related HEP R&D activities that are enabled by C$^3$ R&D, infrastructure requirements and siting options.

physics.acc-ph↗

arXiv2022

Strategy for Understanding the Higgs Physics: The Cool Copper Collider

A program to build a lepton-collider Higgs factory, to precisely measure the couplings of the Higgs boson to other particles, followed by a higher energy run to establish the Higgs self-coupling and expand the new physics reach, is widely recognized as a primary focus of modern particle physics. We propose a strategy that focuses on a new technology and preliminary estimates suggest that can lead to a compact, affordable machine. New technology investigations will provide much needed enthusiasm for our field, resulting in trained workforce. This cost-effective, compact design, with technologies useful for a broad range of other accelerator applications, could be realized as a project in the US. Its technology innovations, both in the accelerator and the detector, will offer unique and exciting opportunities to young scientists. Moreover, cost effective compact designs, broadly applicable to other fields of research, are more likely to obtain financial support from our funding agencies.

hep-ex↗

arXiv2022

Design, fabrication, and tuning of a THz-driven electron gun

We present the design, fabrication, and low power testing of a THz-driven field emission electron gun. The two cell standing-wave gun is designed to be powered by a 110 GHz gyrotron and produce 360 keV electrons with 500 kW of input power. Several gun structures were fabricated using a high precision diamond turned mandrel and copper electroforming. The field emission source is a copper tip with a 50 $μ$m radius inserted halfway into first cell. The frequencies of the cavity resonances were mechanically tuned using azimuthal compression. This work presents electromagnetic and particle simulations of the design and cold test measurements of the fabricated structures.

physics.acc-ph↗

arXiv2022

Advanced RF Sources R&D for Economical Future Colliders

The high power RF system will be a significant budgetary driver for any future collider. An order-of-magnitude improvement in cost/capability is needed, and as a result, a robust R&D program in next-generation, economical RF sources is essential. In this paper, we discuss the challenges and opportunities that arise from advancing the state of the art in these devices. Specifically, research initiatives in new circuit topologies, advanced manufacturing techniques, and novel alternatives to conventional RF source components are discussed.

physics.acc-ph↗

arXiv2021

C$^3$: A "Cool" Route to the Higgs Boson and Beyond

We present a proposal for a cold copper distributed coupling accelerator that can provide a rapid route to precision Higgs physics with a compact 8 km footprint. This proposal is based on recent advances that increase the efficiency and operating gradient of a normal conducting accelerator. This technology also provides an $e^{+}e^{-}$ collider path to physics at multi-TeV energies. In this article, we describe our vision for this technology and the near-term R&D program needed to pursue it.

hep-ex↗