Transition Edge Research Articles

Enhancing fault tolerance of balanced hypercube networks by the edge partition method

Interconnection networks are key component of parallel and distributed systems. As the network scale increases, the growing number of link failures becomes inevitable. Therefore, how to enhance the fault tolerance of the network has become a research issue in parallel and distributed systems. Recently, two new metrics based on edge partition in networks have been introduced, called matroidal connectivity and conditional matroidal connectivity. Existing research indicates that they significantly enhance the fault tolerance of alternating group networks and star networks compared to other indicators such as g-component edge connectivity and g-extra edge connectivity. In this work, we consider the matroidal connectivity and conditional matroidal connectivity of the n-dimensional balanced hypercube BHn, a class of networks with vertex transitivity and edge transitivity, and theoretically demonstrate their high fault tolerance in BHn. Furthermore, through numerical simulation, it is observed that the matroidal connectivity and conditional matroidal connectivity of BHn are greater than the g-component edge connectivity and g-extra edge connectivity of BHn, which implies that (conditional) matroidal connectivity can further improve BHn' fault tolerance.

Rare event searches with cryogenic detectors

Cryogenic detectors can detect the smallest energy depositions via the scattering of the incoming particle with the detector material. The deposited energy leads to minimal temperature rises of a few μ K , read out via transition edge sensors and SQUIDs. Using scintillating crystals as detector material offers the possibility of discriminating between nuclear recoils from dark matter scattering and electromagnetic background events. The CRESST experiment pioneered this technology and is still among the most sensitive experiments searching for sub-GeV dark matter particles. The technology is now also used by other experiments for dark matter searches (COSINUS) and for measuring coherent elastic neutrino-nucleus scattering (NUCLEUS). We discuss cryogenic detectors’ detection principle and their application. We present the latest dark matter results from CRESST, a new type of background, and the status of the COSINUS and NUCLEUS experiments. This article is part of the theme issue ‘The particle-gravity frontier’.

Nonlinear Kinetic Inductance Sensor

The concept of nonlinear kinetic inductance sensor (NKIS) of electromagnetic radiation is proposed. The idea is based on divergency of kinetic inductanceLk∼dq/dI(ℏqis a momentum of superconducting electrons,Iis a supercurrent) of hybrid superconductor/normal metal (SN) bridge at currentI*Idep(Idepis a depairing current of the hybrid) and temperatureT* much smaller than critical temperatureTc. It makes possible to have large change of phase differenceδϕalong SN bridge in current biased regime atI≃I*even for small electron temperature increase. Appearance ofδϕis accompanied by the change of the current and magnetic flux through the coupled superconducting ring which could be measured with help of superconducting quantum interference device (SQUID). In some respect proposed sensor may be considered as a superconducting counterpart of transition edge sensor (TES) those work is based on large derivativedR/dT(Ris a resistance) nearTc. Because atI≃I*SN bridge is in gapless regime there is no low boundary for frequency of detected electromagnetic radiation. Our calculations show that such a sensor can operate in single photon regime and detect single photons with frequencyν≳10 GHz. We argue that the nontrivial dependenceI(q)of SN bridge could be also used in detectors of continuous electromagnetic radiation, current and magnetic field sensors.

Superconducting transition edge bolometer for high-flux neutron detection

Needs for neutron detection and monitoring in high neutron flux environments are increasing in several different fields. A completely solid-state, current mode bolometric detector is constructed as a solid substrate transition edge sensor based on a high-Tc\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_c$$\\end{document} superconducting meander. The detector consists of four individual pixels of which three pixels include 10B4C\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${^{10}{\\hbox {B}}_{4}\\hbox {C}}$$\\end{document} neutron absorption layers. The absorbed energy per neutron absorption reaction is modelled and compared to experimental data. The response of the tested detector is directly correlated to a cold neutron beam with a flux of 1.8×108n/cm2/s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${1.8\ imes 10^{8}}\\,{\\hbox {n}/{\\hbox {cm}}^2/\\hbox {s}}$$\\end{document} modulated by a slit. The signal is found to be an order of magnitude higher than the thermal background. The dynamics described by the temporal saturation constants is governed by a modulation frequency less than 1Hz\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${1}\\hbox { Hz}$$\\end{document}. The thermal response is dynamic and never fully saturates for 50s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${50}\\hbox { s}$$\\end{document} exposures. The efficiency for this proof-of-principle design is 1–2%. Possibilities for optimization are identified, that will increase the efficiency to become comparable to existing solid boron-10 detectors. The existing detectors with event-based read-out have limited functionality in high flux environments. The superconducting bolometer described in this work using current-mode readout will pave the way for high flux applications.

Twitter Self-Organization to the Edge of a Phase Transition: Discrete-Time Model and Effective Early Warning Signals in Phase Space

Many real-world systems of various origins are capable of self-organization to the edge of a phase transition, characterized by avalanche-like behavior. Therefore, it is important, by observing the behavior of early warning measures for dynamical series generated by systems, to timely see the early warning signals (precursors) of such self-organization and, if necessary, take preventive measures. To date, convincing evidence of self-organization to the edge of a phase transition has been obtained, but no effective precursors for this self-organization have been found. This research explores precursors for the Twitter self-organization based on the analysis of the behavior of measures directly related to the critical slowdown of the network and measures of the phase space reconstructed by the Takens method for the series of the number of network users creating avalanches of retweets in the network, corresponding to the three debates of the 2016 United States Presidential Election. We hydrated the relevant Tweet IDs, which were obtained from the Harvard Dataverse using the Social Feed Manager, to form this series. Preliminarily, we explore the potential of measures for early detection of self-organization of sandpile cellular automata as systems with Twitter-equivalent self-organization mechanisms. The equivalence is justified in the proposed discrete-time model for Twitter self-organization to the edge of a phase transition. It is found that there are more moments of the Twitter self-organization than the moments of time when debates started, and Twitter stays at the edge of a phase transition longer than the debate lasts. The effective measures, as the measures with the lowest number of false early warning signals, among all studied measures and for all studied systems, are dispersion and correlation dimension. Obtained results are practically important in the design and implementation of early warning systems for the systems with similar mechanisms for sandpile cellular automata self-organization to the edge of a phase transition.

Magnetic field sensitivity of transition edge sensors

Understanding the magnetic field sensitivity of transition edge sensors (TESs) is vital in optimising the configuration of any magnetic shielding as well as the design of the TESs themselves. An experimental system has been developed to enable the investigation of the applied magnetic field direction on TES behaviour, and the first results from this system are presented. In addition, measurements of the effect of applied magnetic field magnitude on both supercurrent and bias current are presented. The extent to which the current theoretical framework can explain the results is assessed and finally, the impact of this work on the design of TESs and the design of magnetic shielding is discussed.

The ground state, localization, and chiral edge dynamics of a three-legged bosonic magnetic ladder

Three-legged bosonic/fermionic magnetic ladder, reproducing the main features of magnetic lattice systems, is an ideal model to study the edge-bulk coupling and chiral edge dynamics, which are a hallmark of quantum Hall physics. Here, the ground state transition, localization, and chiral edge (bulk) states of an interacting three-legged bosonic magnetic ladder are studied analytically and numerically. When the system is in a quasi-steady state, using variational analysis, the threshold for the transition from zero momentum state to plane wave state is obtained. The energy spectrum, the ground state diagram, the chiral current of the system are presented, and the chiral current reversal at the state transition point is observed. Furthermore, the localization and its stability in the system are discussed, and rich localized phenomena (diffusion, breather, soliton, and self-trapping) are predicted. Stable soliton/breather prefers to form an edge state, while the self-trapping is favorite to form a bulk state, i.e. localized edge and bulk states are obtained. Particularly, for the unstable soliton in the ground state or metastable state, different kinds of chiral edge/bulk state and edge-bulk coupling are observed. The stability of the localized states, the edge-bulk coupling characteristics, and the chirality of the system depend on the energy band structure of the system. Additionally, a controllable transition between localized edge state and bulk state is realized by quenching the soliton state. We proposed a theoretical evidence to design and manipulate edge-bulk coupling and different kinds of localized/chiral edge (bulk) states in three-legged bosonic magnetic ladder.

Integrated Broadband Filter with Sharp Transition Edges Based on SiN and SiON Composite Waveguide Coupler

Broadband filters with sharp transition edges are important elements in diverse applications, including Raman and fluorescence spectral analysis, wideband wavelength-division multiplexing (WDM), and multi-octave interferometry. While the multi-layer thin-film interference broadband filter has been widely applied in various free-space optical systems, its integrated counterpart is still far from mature, which is also highly desired for constructing chip-scale miniature optical modules. In this article, we design, fabricate, and characterize an integrated broadband filter with sharp transition edges. An adiabatic coupler based on silicon nitride (SiN) and silicon oxynitride (SiON) composite waveguide is employed here. Long-pass, short-pass, band-pass, and band-stop filters can be realized in a single design of the composite waveguide coupler for a specific wavelength range, with only a difference in the SiN taper waveguide width. Experimental results with a roll-off value of larger than 0.7 dB nm−1 and a 15 dB extinction ratio (ER) are presented.

On the enumeration of plane bipolar posets and transversal structures

We show that plane bipolar posets (i.e., plane bipolar orientations with no transitive edge) and transversal structures can be set in correspondence to certain (weighted) models of quadrant walks, via suitable specializations of a bijection due to Kenyon, Miller, Sheffield and Wilson. We then derive exact and asymptotic counting results. In particular we prove (computationally and then bijectively) that the number of plane bipolar posets on n+2 vertices equals the number of plane permutations (i.e., avoiding the vincular pattern ▪ ) of size n. Regarding transversal structures, for each v≥0 we consider tn(v) the number of such structures with n+4 vertices and weight v per quadrangular inner face (the case v=0 corresponds to having only triangular inner faces). We obtain a recurrence to compute tn(v), and an asymptotic formula that for v=0 gives tn(0)∼c(27/2)nn−1−π/arccos(7/8) for some c>0, which also ensures that the associated generating function is not D-finite.

A Combined Theoretical and Experimental Investigation of 3D Ternary Perovskite‐Like Silver Iodobismuthate

AbstractLead‐free ternary bismuth halide perovskites A3Bi2X9 have gained much attention as a solution for toxic and unstable lead halide perovskites due to their facile solution processability, high optical absorption coefficient, and high stability. However, their photovoltaic performance remains poor due to their wide bandgap (∼2 eV), and poor charge transport properties stem from their low‐dimensional crystal structure. To promote the 3D structure and reduce the bandgap of ternary Bi‐halide perovskites, we replace the alkali elements at the A‐site with the transition element Ag+ to obtain a new class of perovskite‐like materials named rudorffites AgaBibIa+3b. We investigated the photophysical properties of AgBiI4 by a combined theoretical and experimental approach. Our DFT‐PBE‐SOC predicted band gap for cubic defect spinel AgBiI4 is 2.01 eV, while that obtained for spin‐coated AgBiI4 film is 1.67 eV. Furthermore, the strong p‐p band edge transition leads to high optical absorption in this material. Finally, a photodetector device fabricated using AgBiI4 shows excellent photoresponsivity (183 μA/W) and detectivity (20.93×108 Jones) with a fast rise/decay time of 0.27 s/0.29 s. This newly explored semiconductor class can be a promising and stable choice for advanced optoelectronic devices.

High kinetic inductance NbTiN films for quantum limited travelling wave parametric amplifiers

A wide-bandwidth and low-noise amplification chain in the microwave regime is crucial for the efficient read-out of quantum systems based on superconducting detectors, such as Microwave Kinetic Inductance Detectors (MKIDs), Transition Edge Sensors (TESs), Magnetic Microcalorimeters (MMCs), and RF cavities, as well as qubits. Kinetic Inductance Travelling Wave Parametric Amplifiers (KI-TWPAs) operated in a three-wave mixing fashion have demonstrated exceptional dynamic range and low-noise performance, approaching the quantum limit. These amplifiers can be fabricated using a single layer of a high kinetic inductance film as weakly dispersive artificial transmission lines, with the ability to control the phase-matched bandwidth through dispersion engineering. In this study, we present the optimisation of the rf sputter-deposition process of NbTiN films using a Nb80%Ti20% target, with the goal of achieving precise control over film characteristics, resulting in high kinetic inductance while maintaining a high transition temperature. The parameter landscape related to the different sputtering conditions, such as pressure, power, and nitrogen flow, has been explored and the film thickness has been used as a fine-tuning parameter to adjust the properties of the final NbTiN films used for the fabrication of KI-TWPAs. As a final result, we have obtained a NbTiN film with a kinetic inductance of 8.5 pH/sq which we have exploited to fabricate KI-TWPA prototype devices, showing promising amplification performance.

Housing in Post-Growth Society: Japan on the Edge of Social Transition

Housing in Post-Growth Society: Japan on the Edge of Social Transition

Isogonal embeddings of interwoven and self-entangled honeycomb (hcb) nets and related interpenetrating primitive cubic (pcu) nets.

Two- and three-periodic vertex-transitive (isogonal) piecewise-linear embeddings of self-entangled and interwoven honeycomb nets are described. The infinite families with trigonal symmetry and edge transitivity (isotoxal) are particularly interesting as they have the Borromean property that no two nets are directly linked. These also lead directly to infinite families of interpenetrating primitive cubic nets (pcu) that are also vertex- and edge-transitive and have embeddings with 90° angles between edges.

Effective Thermal Properties of a HTS Transition Edge Bolometer for High‐Flux Neutron Detection

AbstractMany applications require monitoring of increasingly high neutron flux levels. Pre‐neutron characterization is performed of a superconducting transition edge bolometric device, sensitive to neutrons by an enriched boron carbide (10B4C) layer. Heat from the absorption of neutrons is simulated using an attenuated laser, while the detector is cooled to the critical temperature, Tc. Frequency dependent (4–25 Hz) and constant input power measurements are performed on a 10B4C‐coated and a non‐coated pixel. Results are used to fit a two lumped element thermal model. The effective specific heat is highly dependent on the input pulse duration due to the interconnected stack structure. For modulated pulses, the active volume in the thermal circuit is the full depth of the substrate in the area under the pixel. For constant power input, a large portion of the substrate is heated and the interface conductivities to the cold finger are found to be important. The detectivity is D* = 3.5 × 108 , and is only slightly lower than similar detectors. Understanding the dynamics of the detector better and using neutron excitation, it is expected that optimizations can lead to an equally good detector for cold to thermal neutrons at flux levels >106 n cm−2s−1.

Improving defocus blur detection via adaptive supervision prior-tokens

The Defocus Blur Detection (DBD) technique is devised to accurately identify regions of blurriness within images. The prediction difficulty of defocused pixels is closely associated with their spatial location. Owing to the cluttered background, pixels near the edges are more prone to erroneous predictions. To address the issue of uneven pixel distribution at the edges of defocused regions, we deliberately decouple the original labels into Prior-Tokaens: Edge Transition Detail Region (EDR) and Structure Body Region (SBR). Subsequently, we propose a novel adaptive multi-supervised network comprising a feature extraction module, a feature fusion network (FFN), and a Multi-scale Channel Attention Module (MCAM). This method harnesses complementary features between SBR and EDR, furnishing a tailored feature learning strategy that outperforms traditional single-supervised techniques. Furthermore, considering that features generated with varying receptive fields contain information at different levels, we introduce MCAM to identify feature pixels at different scales, enhancing semantic relevance. Moreover, for images with complex scenes, an adaptive learning scheme is developed to selectively fuse low-level detail features and high-level semantic information, thereby enhancing the model's generalization capability. The proposed approach outperforms state-of-the-art techniques on various evaluation metrics, as demonstrated through qualitative and quantitative analyses of popular public datasets.

Mid-infrared modulated photoluminescence mapping to investigate in-plane distributions of bandedge transitions in As-doped HgCdTe

In-plane distribution of band edge electronic structure of the narrow-gap arsenic (As)-doped HgCdTe is a crucial topic fundamentally and technically for mid-infrared detector array but hard to be investigated for long experimentally. This work reports a demonstration of the modulated photoluminescence (PL) mapping carried on As-doped HgCdTe, with the spatial resolution of a typical array pixel scale and with the elaborate band edge transitions being distinguished. Curve fittings related to the bandgap and to the impurities of Hg vacancy (VHg), As donor (AsHg), and AsHg–VHg pair are confirmed for PL mapping assisted by a temperature-dependent PL analysis. The spatial non-uniformity of Cd composition and the distributions of impurity relative concentrations are derived. Correlation analysis suggests that the As atom directly replacing the Hg atom in the complete lattice and the As atom occupying the already-existing VHg are the two approaches for the AsHg formation during As doping. The non-uniform band edge properties may lead to the in-plane conductivity fluctuation detrimental to the array performance. The results indicate the significance of probing the band edge impurity uniformity of As-doped HgCdTe for arrays fabrication, and the modulated PL mapping serving as a desirable and effective tool.

A 220 GHz superconducting titanium transition edge sensor array developed for cosmic microwave background experiments

In this paper, we report on the design, fabrication, and characterization of a 220 GHz superconducting transition edge sensor (TES) array developed for ground-based cosmic microwave background (CMB) experiments. Unlike conventional TES arrays adopting thermometers made of bilayer superconducting films, the TES array has thermometers made of simpler single-layer titanium (Ti) film deposited on a suspended silicon nitride (SiN x ) membrane. The thermal weak link is realized by releasing the TES’s thermal island including the Ti thermometer by dry etching with xenon difluoride (XeF2), giving a typical thermal conductance of 25 pW K−1. Its thermal-conductance mechanism is further studied by fitting the measured TES’s complex impedance with a three-block thermal model. The dark and optical noise equivalent power (NEP) of a superconducting TES are both measured. Despite existing lens reflection and dielectric loss in the superconducting microstrip line, its typical optical NEP reaches 100 aW Hz−0.5, which meets the sensitivity requirement for ground-based CMB experiments.

In-Situ Analysis of Chronopotentiometry Data to Predict Electrodeposition Rates

Often in MEMS or NEMS microfabrication R&D, many single layer “test” samples are created prior to committing more complex multiple layer “device” samples which require more time and effort to create. Ideally, much of the R&D can focus on less critical test samples and the experimental results can then be applied to more valuable device wafers. We investigated tin electroforming into patterned polymer molds creating Meissner-Effect Transition-Edge-Sensor (ME-TES) devices1 and found multiple variables changed between the test and device samples making it difficult to target a desired tin metal thickness. These variables were analyzed and distilled down to two: (I) area and (II) the measured voltage at constant current 30 seconds after plating started. In addition to the underlying analysis, a Graphical User Interface (GUI)2 was developed in R to quickly calculate and predict in-situ tin electroplating rates regardless of uncontrolled variables in the sample.ME-TES devices required a final tin plating feature height of 8-12 microns for 50-micron diameter discs coupled with patterned niobium electrical traces3. During chronopotentiometry experiments, two samples were plated for 1 minute and 18 minutes, respectively – both achieving the target height of 10 microns. This extreme variability in rate caused the height to undershoot or overshoot within just a few minutes of plating. Many variables were collected into a database and analyzed including wafer design layout, electrochemical methods, chemistry make-up, electrochemical setup, the use of a reference electrode, current density, voltage, mounting technique, height, device size, and surface roughness across the substrate. The resulting GUI resulted in fewer necessary test samples, reduced processing time, and improved accuracy in plating thickness.(1) Finnegan, P. Packaging & Solid-state Materials and Fabrication Processes. In Packaging & Solid-state Materials and Fabrication Processes, June 2023.(2) St. John, C. “R Shiny User Interface for Electrochemical Development.” In CoDA, Santa Fe NM, March 2023.(3) Arrington, C.L. Optimizing Tin Electroplating for MEMS Meissner-Effect Transition Edge Sensors. In 243rd ECS Meeting with SOFC-XVIII, Boston, MA, 2023.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.SAND2022-10287A

Advances in superconductor quantum and thermal detectors for analytical instruments

Analytical instruments or scientific instruments are indispensable for scientific research and industry. The analytical instruments require a detector that converts physical quantities to be measured (measurands) to electric signals. This Tutorial describes the basics of quantum and thermal detectors, the operation principles of superconductor detectors, and the ultimate performance of state-of-art analytical instruments with superconductivity. We still face fundamental issues, such as the classical Fano factor, the relation between energy gap and mean carrier creation energy, quasiparticle dynamics, and the intermediate state in the middle of superconducting transition; and engineering issues, such as the small sensitive area and the spatially nonuniform response. Nevertheless, enormous efforts have matured superconductor detectors, which enables us to solve the inherent problems of conventional analytical instruments. As an example of the analytical results, we describe x-ray spectroscopy and mass spectrometry at our institute by using three detector types: superconductor tunnel junction, transition edge sensor, and superconductor strip. Microwave kinetic inductance and metallic magnetic calorimetric types are also described. The analytical results may contribute to a wide range of fields, such as dentistry, molecular biology, energy-saving society, planetary science, and prebiotic organic molecules in space.

Development of Transition Edge Sensors for the Detection of Secondary Electrons

Secondary electrons generated when carbon ions go through the body are considered to be playing a major role in damaging the DNA of cancerous cells. To fully understand the mechanism of carbon ions, experimental and quantitative analysis on the energy and the behavior of these electrons are important. Therefore, we have started the development of TES arrays for the detection of secondary electrons. By performing simulations using Geant4, we have confirmed that the superconducting thin film of a TES is able to stop the electrons. We have also found that relatively high energy secondary electrons might have an influence on the energy spectrum of electrons having energies lower than 100 eV. We are currently fabricating a prototype 2-pixel TES array for the detection of electrons.