arXiv subjects

T. Martin

Publications and source records attributed to T. Martin.

At least 19 recordsLinked to original sources

arXiv2026

P-ONE-1: the first detector line of the Pacific Ocean Neutrino Experiment

Neutrino telescopes instrument optically transparent media with three-dimensional arrays of photosensors to detect Cherenkov radiation induced by neutrino interactions within or near the instrumented volume. The small cross-sections of the weak interaction and the low neutrino fluxes above TeV energies require vast detector volumes, which only natural media on Earth can realistically provide. Spurred by the detection of the first neutrino sources by the IceCube Neutrino Observatory, a new generation of neutrino telescopes is emerging to increase the global instrumented volume and detection sensitivity. The Pacific Ocean Neutrino Experiment (P-ONE) aims to install such a telescope in the Northeast Pacific Ocean, building on established neutrino telescope design targets in collaboration with Ocean Networks Canada (ONC). This article presents the design, integration, and testing of the first P-ONE line, P-ONE-1, in preparation for its deployment and integration into ONC's deep-sea observatory NEPTUNE. Alongside the detector design and integration methods, we detail in-air and in-water system-level validation performed at several test sites in Canada, culminating in the successful construction of P-ONE-1 and its preparation for deployment.

physics.ins-det↗

arXiv2026

Characterization of the R14374-10 photomultiplier tube for the Pacific Ocean Neutrino Experiment

The Pacific Ocean Neutrino Experiment (P-ONE) is a planned cubic-kilometer-scale neutrino telescope that will be deployed in the Pacific Ocean, leveraging deep-sea infrastructure operated by Ocean Networks Canada (ONC). The first detector line will deploy 320 3-inch Hamamatsu R14374-10 photomultiplier tubes (PMTs) to detect Cherenkov light produced by charged particles propagating through water, as well as light from calibration sources and optical backgrounds. This article presents the systematic characterization of all PMTs to be integrated into the first detector line prior to deployment, ensuring compliance with all detector acceptance criteria. All PMTs satisfy the specified performance criteria: the average transit-time spread (TTS) was measured to be $1.73\pm 0.15\,$ns, and the average charge resolution at a gain of \num{5e6} was $0.43\pm 0.03\,$pC; the average after-pulse rate was measured to be around 6$\,\%$. The integrated P-ONE data acquisition (DAQ) system was also tested and cross-validated against a laboratory digitization system. The second part of the paper presents an in-depth characterization of a subset of six PMTs, focusing on the key properties required for detector simulations, including linearity, after-pulse rate, quantum efficiency, and relative collection efficiency. PMT linearity was measured at a gain of \num{5e6} using the complete P-ONE readout electronics, and the response was found to remain linear for signals up to 150 photoelectrons. After-pulse contributions from $\text{Cs}^{+}$, $\text{He}^{+}$, and other ions were identified in the subset. The peak quantum efficiency was measured to be $27.0\pm0.7\,\%$ at 395\,nm. Using measurements of the relative detection efficiency, the collection efficiency was found to differ by a wavelength-independent offset of 10--15$\%$ across the measured wavelength range.

physics.ins-det↗

arXiv2026

Optical calibration systems of the Pacific Ocean Neutrino Experiment

This work presents the design and performance characterization of the optical calibration systems produced for the Pacific Ocean Neutrino Experiment (P-ONE), which target gain, energy and time calibration in the detector. These systems include novel light-pulse driver circuitry based on gallium nitride field-effect transistor technology and its application to directional and isotropic, self-monitoring optical calibration instruments. A total of 330 directional light pulsers and two isotropic, 17-inch calibration modules (P-CALs) were produced for the first P-ONE line. We present the designs and performance of both the directional and isotropic calibration devices and perform detailed optical characterizations of both full-production batches. In a wavelength range of $365 - 520\,$nm, our developed driver circuits achieve emission intensities up to $10^{11}\,$photons and pulse widths as small as $1.4\,$ns, respectively. Light-pulse drivers and self-monitoring electronics in the P-CAL were characterized using the same experimental setup, and the instrument's optical-isotropy design was optimized in combination with a dedicated GEANT4-based simulation framework. The optimized P-CAL achieves a simulated isotropy grade of $1.00 \pm 0.01$ across the entire $4π\,$solid angle range. These simulation investigations were explicitly confirmed by dedicated measurements in both air and water using two independent experimental setups, and we report the results. With this, a detailed performance estimate for deployed P-CAL modules in P-ONE was possible.

physics.ins-det↗

arXiv2026

Long term study of sedimentation and biofouling at Cascadia Basin, the site of the Pacific Ocean Neutrino Experiment

STRings for Absorption Length in Water (STRAW)-a and b were pathfinder instruments deployed to characterize the anticipated site of the Pacific Ocean Neutrino Experiment (P-ONE), which is a future neutrino telescope that will be located in the North Pacific Ocean. Measurements of the evolution of the optical transmission efficiency from STRAW-a showed a decline over the detector's lifetime for the upward-facing modules. Video footage of the pathfinders strongly suggested this decline was caused by biofouling and sedimentation. We measure the effect of biofouling and sedimentation to be a decrease in the transparency of upward-facing optical surfaces over 5 years of operations. A majority of downward-facing optical surfaces, which will dominate P-ONE's sensitivity to astrophysical sources, showed no visible biofouling. Extrapolations motivated by biological growth models estimated that these losses started around 2.5 years after deployment, and suggest a reduction in transparency ranging from 35$\%$ of the original to complete obscuration for the upward-facing modules. Samples of biofouling were taken in order to identify the microbial diversity of these organisms and inform potential intervention strategies. Results of the microbial samples and a candidate anti-biofouling strategy that will be tested on upcoming P-ONE instruments are discussed.

hep-ex↗

arXiv2025

Development & first Performance evaluation of multi-element monolithic HPGe detector for X-ray spectroscopy

The first operational prototype of a high-purity Germanium (HPGe) detector developed within the European LEAPS-INNOV project is presented in this work. This prototype features a monolithic, multi-element sensor optimized for high-resolution X-ray spectroscopy in the hard X-ray regime, capable of handling high count rates (20-250 kcps/mm2) across a broad energy range (5-100 keV). We discuss here a complete laboratory-based characterization of the detector's performance, as well as an on-beam evaluation at the BM05 beamline of the ESRF synchrotron facility, using monochromatic X-rays in the 20-50 keV energy range. We provide a detailed performance assessment that also includes a phenomenological defect-depth estimation model.

physics.ins-det↗

arXiv2025

Noises in a two-channel charge Kondo model

We investigate fluctuations of electric and heat currents, along with their cross-correlations, in a two-channel charge Kondo circuit driven by either a voltage bias or a temperature gradient applied across the weak link. The ratios of voltage-driven electric/heat noise to the applied voltage $V$ exhibit oscillations with the gate voltage $N$, resembling the behavior of the thermoelectric coefficient $G_T$. In contrast, the ratios of temperature-driven electric/heat noise to the temperature difference $ΔT$ vary with $N$ in a manner analogous to the thermal coefficient $G_H$ or the electric conductance $G$. The mixed noise, which is defined as the correlation function between electric and heat currents, displays behavior opposite to that of the above noises. The logarithmic temperature dependence of these noises signals non-Fermi-liquid behavior, while their oscillations with gate voltage reflect the roles of particle-hole and time-reversal symmetries in thermoelectric transport. Our results demonstrate that the fundamental relations linking voltage- and temperature-induced noises to thermoelectric transport across a tunnel junction persist beyond the Fermi-liquid paradigm.

cond-mat.mes-hall↗

arXiv2025

Prototype acoustic positioning system for the Pacific Ocean Neutrino Experiment

We present the design and initial performance characterization of the prototype acoustic positioning system intended for the Pacific Ocean Neutrino Experiment. It comprises novel piezo-acoustic receivers with dedicated filtering- and amplification electronics installed in P-ONE instruments and is complemented by a commercial system comprised of cabled and autonomous acoustic pingers for sub-sea installation manufactured by Sonardyne Ltd. We performed an in-depth characterization of the acoustic receiver electronics and their acoustic sensitivity when integrated into P-ONE pressure housings. These show absolute sensitivities of up to $-125\,$dB re V$^2/μ$Pa$^2$ in a frequency range of $10-40\,$kHz. We furthermore conducted a positioning measurement campaign in the ocean by deploying three autonomous acoustic pingers on the seafloor, as well as a cabled acoustic interrogator and a P-ONE prototype module deployed from a ship. Using a simple peak-finding detection algorithm, we observe high accuracy in the tracking of relative ranging times at approximately $230-280\,μ$s at distances of up to $1600\,$m, which is sufficient for positioning detectors in a cubic-kilometer detector and which can be further improved with more involved detection algorithms. The tracking accuracy is further confirmed by independent ranging of the Sonardyne system and closely follows the ship's drift in the wind measured by GPS. The absolute positioning shows the same tracking accuracy with its absolute precision only limited by the large uncertainties of the deployed pinger positions on the seafloor.

physics.ins-det↗

arXiv2025

Next Generation Multi-element monolithic Germanium detectors for Spectroscopy: First integration at ESRF facility

The XAFS-DET work package of the European LEAPS-INNOV project is developing a high-purity Germanium detectors for synchrotron applications requiring spectroscopic-grade response. The detectors integrate three key features: (1) newly designed monolithic Germanium sensors optimised to mitigate charge-sharing events, (2) an improved cooling and mechanical design structure supported by thermal simulations, and (3) complete electronic chain featuring a low-noise CMOS technology-based preamplifier. enabling high X-ray count rate capability over a broad energy range (5-100 keV). This paper discusses the first integration and characterization of one of the two multi-element Ge detectors at the European Synchrotron Radiation Facility (ESRF). The integration phase included validating high-throughput front-End electronics, integrating them with the Ge sensor, and operating them at liquid nitrogen temperature, in addition to the experimental characterization, which consists of electronics noise study and spectroscopic performance evaluation.

physics.ins-det↗

arXiv2025

Progress in the Development of Multi-Element Monolithic Germanium Detectors in LEAPS-INNOV Project: Insights from Detector Performance Simulation

This study presents a detailed simulation-based analysis of the detection limits of multi-element monolithic Germanium (Ge) detectors to cadmium traces in environmental soil samples. Using the capabilities of the Geant4 Monte Carlo toolkit in combination with the Solid State Detector Package, we evaluated the detection limit variation with the sample-to-detector distances and photon flux. These simulations were conducted to mimic realistic conditions, with a photon flux measured by the SAMBA beamline at the SOLEIL synchrotron facility. Our findings for the detection limit for trace amounts of pollutants in low concentrations like cadmium in the soil provide valuable insights for optimizing experimental setups in environmental monitoring and synchrotron-based applications, where precise detection of trace elements is critical.

physics.ins-det↗

arXiv2025

The Non-Uniform Expansion of the Crab Nebula

We present extensive proper motion measurements of the Crab Nebula made from Canada-France-Hawaii Telescope MegaPrime/MegaCam images taken in 2007, 2016, and 2019. A total of 19974 proper motion vectors with uncertainty $<10$\,mas\,yr$^{-1}$ located over the majority of the Crab Nebula are used to map the supernova remnant's two-dimensional expansion properties that reflect the dynamics of the original explosion, acceleration of ejecta imparted by spin-down energy from the pulsar, and interaction between the ejecta and surrounding cicumstellar material (CSM). The average convergence date we derive is 1105.5 $\pm$ 0.5 CE, which is 15-35 yr earlier compared to most previous estimates. We find that it varies as a function of position angle around the nebula, with the earliest date and smallest proper motions measured along the equator defined by the east and west bays. The lower acceleration of material along the equatorial plane may be indicative of the supernova's interaction with a disk-like CSM geometry. Comparing our measurements to previous analytical solutions of the Crab's expansion and our own numerical simulation using the moving mesh hydrodynamics code \texttt{Sprout}, we conclude that the ejecta have relaxed closer to homologous expansion than expected for the commonly adopted pulsar spindown age of $τ\sim 700$ yr and a pulsar wind nebula (PWN) still evolving inside the flat part of the ejecta density profile. These findings provide further evidence that the PWN has broken out of the inner flat part of the supernova ejecta density profile and has experienced ``blowout''.

astro-ph.HE↗

arXiv2024

Finite width of anyons changes their braiding signature

Anyons are particles intermediate between fermions and bosons, characterized by a nontrivial exchange phase, yielding remarkable braiding statistics. Recent experiments have shown that anyonic braiding has observable consequences on edge transport in the fractional quantum Hall effect (FQHE). Here, we study transport signatures of anyonic braiding when the anyons have a finite width. We show that the width of the anyons, even extremely small, can have a tremendous impact on transport properties and braiding signatures. In particular, we find that taking the finite width into account allows us to explain recent experimental results on FQHE at filling factor $2/5$ [Ruelle et al., Phys. Rev. X \textbf{13}, 011031 (2023)]. Our work shows that the finite width of anyons crucially influences setups involving anyonic braiding, especially when the exchange phase is larger than $π/2$.

cond-mat.mes-hall↗

arXiv2024

Nonreciprocal charge transport and subharmonic structure in voltage-biased Josephson diodes

We study charge transport in voltage-biased single-channel junctions involving helical superconductors with finite Cooper pair momentum. For a Josephson junction, the equilibrium current-phase relation shows a superconducting diode effect: the critical current depends on the propagation direction. We formulate a scattering theory for voltage-biased Josephson diodes and show that multiple Andreev reflection processes cause a rich subharmonic structure in the DC current-voltage curve at low temperatures and small voltages due to Doppler shifts of the spectral gap. In the current-biased case, the diode efficiency has maximal rectification efficiency $η_0\approx 0.4$ for this model. In the voltage-biased case, however, the rectification efficiency can reach the ideal value $η=1$. We also discuss charge transport for NS junctions between a normal metal and a helical superconductor and comment on related models with spin-orbit interactions and magnetic Zeeman fields.

cond-mat.supr-con↗

arXiv2024

Levitons in correlated nano-scale systems

in nanoscale systems in the presence of single-electron excitations generated by Lorentzian voltage drives, termed \textit{Levitons}. These excitations allow to realize the analog of quantum optics experiments using electrons instead of photons. Importantly, electrons in condensed matter systems are strongly affected by the presence of different types of non-trivial correlations, with no counterpart in the domain of photonic quantum optics. After providing a short introduction about Levitons in non-interacting systems, we focus on how they operate in the presence of two types of strong electronic correlations in nanoscale systems, such as those arising in the fractional quantum Hall effect or in superconducting systems. Specifically, we consider Levitons in a quantum Hall bar of the fractional quantum Hall effect, pinched by a quantum point contact, where anyons with fractional charge and statistics tunnel between opposite edges. In this case, a Leviton-Leviton interaction can be induced by the strongly correlated background. Concerning the effect of superconducting correlations on Levitons, we show that, in a normal metal system coupled to BCS superconductors, half integer Levitons minimize the excess noise in the Andreev regime. Interestingly, energy-entangled electron states can be realized on-demand in this type of hybrid setups by exploiting crossed Andreev reflection. The results exposed in this review have potential applications in the context of quantum information and computation with single-electron flying qubits.

cond-mat.mes-hall↗

arXiv2024

Approaching ideal rectification in superconducting diodes through multiple Andreev reflections

We analyze the rectification properties of voltage-biased Josephson junctions exhibiting the superconducting diode effect. Taking into account multiple Andreev reflection (MAR) processes in our scattering theory, we consider a short weak link of arbitrary transparency between two superconductors with finite Cooper pair momentum $2q$. In equilibrium, the diode efficiency is bounded from above in this model, with maximal efficiency $η_0\approx 0.4$. Out of equilibrium, we find a rich subharmonic structure in the current-voltage curve. For high transparency and low bias voltage $V$, the rectification efficiency $η(V)$ approaches the ideal value $η=1$ for $qξ\to 1$ (with coherence length $ξ$).

cond-mat.supr-con↗

arXiv2023

Anyonic statistics revealed by the Hong-Ou-Mandel dip for fractional excitations

The fractional quantum Hall effect (FQHE) is known to host anyons, quasiparticles whose statistics is intermediate between bosonic and fermionic. We show here that Hong-Ou-Mandel (HOM) interferences between excitations created by narrow voltage pulses on the edge states of a FQHE system at low temperature show a direct signature of anyonic statistics. The width of the HOM dip is universally fixed by the thermal time scale, independently of the intrinsic width of the excited fractional wavepackets. This universal width can be related to the anyonic braiding of the incoming excitations with thermal fluctuations created at the quantum point contact. We show that this effect could be realistically observed with periodic trains of narrow voltage pulses using current experimental techniques.

cond-mat.mes-hall↗

arXiv2023

Photo-assisted current in the fractional quantum Hall effect as a probe of the quasiparticle operator scaling dimension

We study photo-assisted transport for the edge states of a two dimensional electron gas in the fractional quantum Hall regime, pinched by a single quantum point contact. We provide a general expression of the photo-assisted current using a Keldysh-Floquet approach, when the AC drive is applied either directly to the edge states, or when it modulates the tunneling amplitude at the quantum point contact. Strikingly, for a simple cosine modulation of the tunneling amplitude, the phase shift of the second harmonic of the photoassisted current is directly related to the scaling dimension of the quasiparticle operators describing the fractional excitations. As the scaling dimension is intimately related to the statistics, our proposal of a gate modulation of the backscattered current provides a diagnosis of the statistics of Laughlin quasiparticles using a simple quantum point contact geometry.

cond-mat.mes-hall↗

arXiv2023

Quasiparticle Andreev reflection in the Laughlin fractions of the fractional quantum Hall effect

Andreev reflection occurs in a normal metal-superconductor junction, when an electron on the normal side can only be transmitted as a Cooper pair in the superconductor, with the reflection of a hole on the normal side. A similar phenomenon can occur in strongly correlated systems, in particular in the fractional quantum Hall effect (FQHE), as the system quasiparticles have a charge $e/m$ different from the electron charge. We study theoretically a setup involving two quantum point contacts (QPC) in the FQHE where Andreev reflection occurs, as charges $e/m$ impinging on the second QPC can only be transmitted as charges $e$, with the reflection of holes of charge $e (1-m)/m $. Using the bosonization formalism, and out-of-equilibrium Keldysh Green function techniques, we provide a full analytical calculation of the current correlations at the outputs of the QPC, both at zero and finite temperature. The ratio between the auto- and cross-correlations of the output currents is a direct manifestation of Andreev reflection. Our results agree with recent experimental observations, and give precious information on the temperature dependence of this ratio.

cond-mat.mes-hall↗

arXiv2023

Quartet currents in a biased three-terminal diffusive Josephson junction

Biasing a three-terminal Josephson junction (TTJ) with symmetrical voltages $0,V,-V$ leads to new kinds of DC currents, namely quartet Josephson currents and phase-dependent multiple Andreev reflection (MAR) currents. We study these currents in a system where a normal diffusive metallic node $N$ is connected to three terminals $S_{0,1,2}$ by barriers of arbitrary transparency. We use the quantum circuit theory to calculate the current in each terminal, including decoherence. In addition to the stationary combination $φ_Q=φ_1+φ_2-2φ_0$ of the terminal phases $φ_i$, the bias voltage $V$ appears as a new and unusual control variable for a DC Josephson current. A general feature is the sign changes of the current-phase characteristics, manifesting in minima of the quartet ``critical current". Those sign changes can be triggered by the voltage, by the junction transparency or by decoherence. We study the possible separation of quartet currents from MAR currents in different regimes of parameters, including an "funnel" regime with very asymmetric couplings to $S_{0,1,2}$. In the regime of low transparency and asymetric couplings, we provide an analytic perturbative expression for the currents which shows an excellent agreement with the full numerical results.

cond-mat.supr-con↗