https://arxiv.org/api/wGSaPG9OnKSPZeyxoQU1lVnSOAY 2026-10-07T14:57:35Z 15 63 0 http://arxiv.org/abs/2609.35556v1 2026-09-28T16:27:15Z

Atomically precise graphene nanoribbons (GNRs) exhibit tunable electronic and magnetic properties governed by edge topology and finite-size effects, which make them versatile platforms for next-generation electronic and spintronic applications. However, the unpaired pi-electrons responsible for their magnetic properties simultaneously make them highly susceptible to chemical degradation under ambient conditions. This intrinsic reactivity poses a central experimental challenge: accessing vibrational and electronic signatures of air-sensitive GNRs during synthesis and under controlled environments without breaking vacuum. Once the material has been exposed to air, standard characterization techniques would probe oxidized or chemically modified species rather than the pristine form. Here, we overcome this limitation by developing a home-built ultra-high vacuum (UHV) Raman platform designed to preserve sample integrity by preventing air exposure and to enable in situ investigation of material properties. The portable Raman vacuum suitcase (RVS) integrates temperature control and precise gas dosing, allowing direct monitoring of growth kinetics, lattice dynamics, and reactive-edge responses under well-defined thermal and chemical environments. Using this platform, we monitor the on-surface synthesis of 7- and 9-atom-wide armchair GNRs (7- and 9-AGNRs), quantify the evolution of 7-AGNR Raman modes over a wide temperature range (162-748 K), and resolve chemical changes upon controlled O2 exposure that are consistent with oxidation at the reactive zigzag sites. These results establish UHV Raman spectroscopy with the RVS as a route to accessing the intrinsic vibrational signatures of low-dimensional quantum materials under controlled environments.

2026-09-28T16:27:15Z Jeong Ha Hwang Amogh Kinikar Lukas Rotach Andres Ortega-Guerrero Carlo A. Pignedoli Klaus Muellen Thorsten G. Englmann Xinliang Feng Pascal Ruffieux Roman Fasel Mickael L. Perrin Gabriela Borin Barin http://arxiv.org/abs/2609.11862v1 2026-09-10T17:41:10Z

The discovery of high-temperature ferromagnetism in the metallic van der Waals (vdW) system Fe$_N$GeTe$_2$ has brought two-dimensional (2D) magnets into technologically relevant temperature scales. Specifically at N = 5, dilution of magnetic moments by nickel substitution counterintuitively achieves a record high Curie temperature of 478~K. Unraveling the origin of this nickel-substitution-induced enhancement is complicated by the compound's structural complexity, coexistent itinerant and local magnetic contributions, and mesoscopic compositional domains. Through coordinated structural and electronic characterization, we identify that the high-T$_C$ magnetic phase arises from a strain-stabilized Fe$_6$GeTe$_2$ nano-precipitate. Combining first-principles calculations and spin- and angle-resolved photoemission spectroscopy (ARPES), we uncover a site-specific electronic landscape in which interior iron atoms primarily host localized moments while the outer iron atoms neighboring the tellurium layers produce spin-polarized itinerant carriers that cross the vdW gap. The large energy cost associated with homogeneous nickel substitution is found to favor the spontaneous precipitation of the crystallographically and electronically ``clean'' high-T$_C$ phase. Finally, we compare metal-rich vdW magnets with binary magnetic alloys, and discuss the unifying roles of nano-precipitates in stabilizing otherwise unattainable bulk phases. Our work provides mechanistic insights into the record-high T$_C$ ferromagnetism in (Fe,Ni)$_{5+δ}$GeTe$_2$, establishing a rigorous foundation for the atomic engineering of vdW magnetic metals informed by direct electronic signatures.

2026-09-10T17:41:10Z 16 pages, 8 figures Tyler L. Werner Department of Applied Physics, Yale University, New Haven, USA Jonathan T. Reichanadter Department of Physics, University of California, Berkeley, Berkeley, USA Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, USA Xiang Chen Department of Physics, University of California, Berkeley, Berkeley, USA Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, USA Pranab K. Nag Department of Physics, Yale University, New Haven, USA Energy Sciences Institute, Yale University, West Haven, USA Luna Y. Liu Department of Applied Physics, Yale University, New Haven, USA Yu-Tsun Shao School of Applied and Engineering Physics, Cornell University, Ithaca, USA Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, USA Hongrui Zhang Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, USA Mingyang Guo Department of Physics, Boston College, Chestnut Hill, USA Wenxin Li Department of Applied Physics, Yale University, New Haven, USA Zhibo Kang Department of Applied Physics, Yale University, New Haven, USA Han Wu Department of Physics and Astronomy, Rice University, Houston, USA Rice Center for Quantum Materials, Rice University, Houston, USA Makoto Hashimoto Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, USA Donghui Lu Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, USA Turgut Yilmaz National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, USA Elio Vescovo National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, USA Sung-Kwan Mo Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, USA Barat Achinuq Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, USA Alexei Fedorov Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, USA Jacob C. Ruff Cornell High Energy Synchrotron Source, Cornell University, Ithaca, USA Ming Yi Department of Physics and Astronomy, Rice University, Houston, USA Rice Center for Quantum Materials, Rice University, Houston, USA Qiong Ma Department of Physics, Boston College, Chestnut Hill, USA Schiller Institute for Integrated Science and Society, Boston College, Chestnut Hill, USA David A. Muller School of Applied and Engineering Physics, Cornell University, Ithaca, USA Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, USA Eduardo H. da Silva Neto Department of Applied Physics, Yale University, New Haven, USA Department of Physics, Yale University, New Haven, USA Energy Sciences Institute, Yale University, West Haven, USA Robert J. Birgeneau Department of Physics, University of California, Berkeley, Berkeley, USA Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, USA Jeffrey B. Neaton Department of Physics, University of California, Berkeley, Berkeley, USA Kavli Energy Nanosciences Institute at Berkeley, Berkeley, USA Yu He Department of Applied Physics, Yale University, New Haven, USA http://arxiv.org/abs/2609.03717v1 2026-09-03T11:51:53Z

La2Mo2O9 (LAMOX) is a promising oxide-ion conductor for intermediate-temperature solid oxide fuel cells, but its practical application is limited by a first-order monoclinic-to-cubic (alpha to beta) phase transition. Here, we investigate the electronic structure of pristine La2Mo2O9 and the Gd/W co-doped composition La1.6Gd0.4Mo1.7W0.3O9 using spin-polarized density functional theory with an on-site Hubbard correction for the localized Gd-4f states. The projected density of states reveals that pristine La2Mo2O9 is an O-2p/Mo-4d charge-transfer oxide in which La contributes negligibly near the band edges. Gd/W co-doping introduces a strongly exchange-split Gd-4f manifold with a majority-minority separation of approximately 1011 eV, substantially redistributes the Mo-4d electronic states through a threefold increase in crystal-field splitting, and reduces the O-2p contribution near the valence-band maximum from 78% to 66%. These electronic signatures are consistent with the experimentally observed lattice contraction, MoO Raman-mode softening, and the non-monotonic evolution of oxide-ion conductivity across the co-doped series. In particular, the pronounced crystal-field splitting and localized Gd magnetism at the highest doping level provide a microscopic electronic explanation for the observed suppression of ionic conductivity. The present results establish an atomistic electronic-structure framework for understanding dopant-induced phase stabilization and oxide- ion transport in Gd/W co-doped LAMOX electrolytes, providing design principles for improved solid oxide fuel cell materials.

2026-09-03T11:51:53Z Conference: International Conference on Advanced Functional Materials and Devices (AFMD-2026) Amogh U. Lanjewar Saurabh Shiwankar Smita Acharya http://arxiv.org/abs/2607.21301v1 2026-07-23T13:26:39Z

Chromium sulfur bromide (CrSBr) is a layered magnetic semiconducting material combining a rich magnetic phase diagram with axis-dependent electronic and optical properties. While defects in CrSBr have been shown to affect magnetic order and excitonic responses, their microscopic nature, atomic structure, and electronic properties are not yet fully understood. In this work, we use scanning tunneling microscopy/spectroscopy (STM/STS) to explore the structure and electronic signatures of two prominent defects in bulk CrSBr. Their structure reflects the symmetries of the underlying lattice, with electronic features near the valence band edge. By comparing experimental data with ab initio simulated STM images, we infer that a common defect corresponds to a b-axis-aligned double sulfur vacancy, in line with findings from a recent growth analysis study. This result advances our understanding of the role of intrinsic defects in shaping the electronic structure of CrSBr.

2026-07-23T13:26:39Z Jonathan Brunette Joost Aretz Kiyoung Jo Aljoscha Soll Zdeněk Sofer Malte Rösner Nathan Guisinger Adina Luican-Mayer http://arxiv.org/abs/2607.09370v1 2026-07-10T12:50:45Z

Access control to networked resources has been a longstanding challenge. The conventional solution relies on authentication mechanisms, which introduce additional complexities associated with Identity and Access Management (IAM). Such systems require user authentication, identity management, and authorization services, while also introducing security risks arising from vulnerabilities, misconfigurations, or implementation flaws. Furthermore, different file formats employ different mechanisms for ensuring authenticity and integrity through digital signatures. For example, PDF documents support the PDF Advanced Electronic Signature (PAdES) standard, whereas plain text files typically lack a standardized mechanism for embedding digital signatures. This paper proposes an architecture based on the Selective Disclosure JSON Web Token (SD-JWT) standard for securely sharing read-only files. The proposed architecture embeds cryptographic signatures and integrity protection directly into the shared resource, providing verifiable authenticity without relying on complex IAM infrastructures, such as centralized user databases, authentication services, or authorization mechanisms. By eliminating these components, the proposed solution simplifies deployment while maintaining strong security guarantees for the distribution of immutable resources.

2026-07-10T12:50:45Z Aditya Mitra Quazi Fariha Tasnim Hristina Mihajloska Trpcheska http://arxiv.org/abs/2606.10221v1 2026-06-08T22:22:33Z

Interpreting metal K-edge spectra of flexible photosensitizers requires a structural model that separates electronic signatures from thermal motion, solvent disorder, and crystal-packing effects. We combine Fe K-edge X-ray absorption measurements with second-generation Car--Parrinello ab initio molecular dynamics and all-electron Gaussian and augmented-plane-wave simulations for an iron(II) N-heterocyclic carbene photosensitizer in acetonitrile solution and in the crystalline phase. Ensemble-averaged spectra reproduce the main near-edge features in both environments and preserve the experimentally observed similarity of the first Fe coordination shell upon dissolution. Comparison with radial distributions extracted from extended fine-structure measurements validates the Fe--N and Fe--C coordination shells sampled by the trajectories, while element-resolved pair distributions explain why higher-shell experimental contrast is rapidly lost. The same dynamical ensembles reveal a broad out-of-plane distribution of the terpyridine nitrogen atom and a nearly octahedral distribution of the Fe-centered coordination planes. The results show that finite-temperature X-ray absorption simulations can provide a compact structural-dynamics picture of molecular transition metal photosensitizers by linking local spectra, solvent-phase ligand motion, and medium-range structural disorder within one trajectory-based description.

2026-06-08T22:22:33Z Patrick Müller Lorena Fritsch Matthias Bauer Thomas D. Kühne http://arxiv.org/abs/2605.21631v1 2026-05-20T18:42:42Z

Tunneling spectroscopy and its evolution are crucial for elucidating the intricate electronic structure and emergent phenomena in quantum materials.Nevertheless, high-quality measurements -- specifically those tracking evolution across temperature and external fields -- remain a formidable challenge. We have fabricated a high-quality $\mathrm{TaO}_x$-based planar tunneling junction by using magnetron sputtering for van der Waals (vdW) superconductors. Using the vdW superconductor $\mathrm{Bi}_2\mathrm{Sr}_2\mathrm{CaCu}_2\mathrm{O}_{8+δ}$ (Bi2212) as a benchmark, this platform yields high-quality tunneling spectra, reproducing the electronic signatures obtained from scanning tunneling spectra acquired from atomically clean surfaces under ultra-high vacuum conditions. This architecture enables high-precision spectroscopy across extensive temperature and magnetic field ranges, offering a universal strategy for probing the electronic structures of diverse two-dimensional systems and facilitating future explorations of material properties.

2026-05-20T18:42:42Z Yixuan Niu Jun Cheng Shiji Ding Zhongxin Guo Shang Wang Chenglong Li Meining Zhang Peng Cai http://arxiv.org/abs/2604.21613v1 2026-04-23T12:39:43Z

Two-dimensional materials can stabilize crystal structures that are absent from their bulk counterparts, offering opportunities for materials design. Here, we report the synthesis of a previously unknown hexagonal Fe$_2$S$_2$ single layer with $β$-CuI structure, a buckled layer of two vertically stacked FeS honeycomb lattices, realized by thermally induced transformation of single layer mackinawite grown on graphene/Ir(111). In situ scanning tunneling microscopy and low-energy electron diffraction reveal a transition from a tetragonal to a hexagonal lattice accompanied by distinct morphological and electronic signatures. The hexagonal Fe$_2$S$_2$ forms reproducibly upon annealing and represents a new structural motif within the Fe-S material family. First-principles calculations identify the $β$-CuI structure as most consistent with experiment. The calculations suggest that on-site Coulomb interactions and magnetic order are relevant to understanding the stability of the new 2D Fe-S compound. The preferred nucleation of single-layer mackinawite, despite being energetically disfavored, is speculated to result from its low edge energy, analogous to the 3D case. Our results establish Fe$_2$S$_2$ as a platform for exploring structural polymorphism in two dimensions and demonstrate that reduced dimensionality can stabilize crystal structures not accessible in bulk materials.

2026-04-23T12:39:43Z Affan Safeer Wejdan Beida Felix Oberbauer Nicolae Atodiresei Gustav Bihlmayer Max Wolfertz Chiara Schlichte Wouter Jolie Stefan Blügel Jeison Fischer Thomas Michely http://arxiv.org/abs/2604.15491v2 2026-05-12T22:32:44Z

Ultrafast melting is fundamentally a structural transition of the ionic lattice, but this rearrangement also reshapes the electronic properties by changing the energy landscape and scattering mechanisms. Although the electrons react almost instantaneously, it is not a priori clear how much lattice disorder is required for a significant response. Here, we show that the onset of melting already produces a clear electronic signature in polycrystalline copper. Using single-shot terahertz time-domain spectroscopy on thin films excited over a wide range of laser fluences, we infer the transient conductivity during the first picoseconds after excitation. The data, supported by two-temperature molecular-dynamics simulations, show that before melting, electron transport is substantially limited by grain-boundary scattering and that melting strongly suppresses this channel. As melting begins at these interfaces, we observe a transient increase in the conductivity that directly marks the onset of the phase transition. More broadly, these results show that ionic and electronic relaxation stages are closely coupled in nonequilibrium laser-driven matter and that optical measurements can resolve distinct stages of melting.

2026-04-16T19:47:57Z Edna R. Toro Tobias Held Armin Bergermann Megan Ikeya Maximilian Maigler Eric R. Sung Dirk O. Gericke Mianzhen Mo Baerbel Rethfeld Siegfried H. Glenzer Benjamin K. Ofori-Okai http://arxiv.org/abs/2604.02443v1 2026-04-02T18:14:54Z

High-pressure xenon gas TPCs with electroluminescent amplification (HPXeEL) provide detailed topological reconstruction of charged-particle trajectories, offering a distinctive two-electron signature for neutrinoless double beta decay ($0ββν$) searches. We have recently proposed ITACA, a detector concept that images both the electron track and the corresponding ion track, carried by the positive ions drifting in the opposite direction. While electrons drift rapidly to the anode for standard EL imaging, the positive ions drift slowly to the cathode with millimetre-scale diffusion, allowing time to determine the event energy and barycenter and to position a movable ion detector at the projected arrival point of the ion cloud. We present a conceptual design of the ITACA detector, addressing key feasibility questions. First, we define the detector geometry and operating parameters for a 1-tonne-scale instrument at 15 bar, including a modular tiled electroluminescent structure. Second, we present the conceptual design of the Magnetically Actuated Rotor System (MARS), the mechanism that positions the ion sensor at any $(r, θ)$ coordinate below the cathode, and show that the expected movement time is fast enough to retain $\sim95\%$ of the drift volume for ion detection, while not significantly perturbing the gas on the scales of the ion drift. Third, we propose using a Topmetal CMOS ASIC-based ion detector as an alternative to the molecular sensor approach described in our original work, enabling real-time, 3D imaging of the ion track without the need for offline laser scanning. Finally, we estimate the sensitivity of the proposed apparatus, showing that enhanced topological discrimination from the ion track, combined with an ultra-low background design, allows exploration of $0ββν$ half-lives in excess of $10^{28}$ yr.

2026-04-02T18:14:54Z 38 pages, 16 figures J. J Gómez-Cadenas L. Arazi G. Martínez-Lema J. Renner S. R. Soleti S. Torelli http://arxiv.org/abs/2603.05608v1 2026-03-05T19:04:40Z

Observing early optical emission from gamma-ray bursts (GRBs) contemporaneous with the MeV prompt emission phase remains rare, requiring rapid-response robotic facilities. The Ondřejov D50 telescope detected the optical counterpart of GRB 250702F at z = 1.520 only 27.8 s after trigger, enabling high-cadence monitoring during the brightest prompt emission pulses. The optical light curve reveals two distinct flares. The first (30 - 100 s) is spectrally consistent with the MeV prompt emission. The second flare (100 - 1400 s) exhibits an unusual morphology (F_nu ~ t^-alpha): a rapid rise to a plateau, followed by a steep decay (alpha ~ 1.6) before transitioning to a standard power-law afterglow (alpha = 0.79). This steep decay phase cannot be explained by nonthermal electrons accelerated at the forward shock, and reverse-shock scenario is disfavored due to the long duration of the flare and the temporal offset from the underlying deceleration time. We interpret the steep decay as the synchrotron frequency of a thermal (Maxwellian) electron population sweeping through the optical band. Modeling yields a non-thermal energy fraction delta ~ 0.8 with the remaining energy heating electrons at characteristic Lorentz factor gamma_th ~ 900. These observations provide evidence for thermal electron signatures in GRB afterglows, consistent with predictions from particle-in-cell simulations of ultra-relativistic collisionless shocks.

2026-03-05T19:04:40Z 8 pages, 4 figures A&A 710, L1 (2026) Martin Jelínek Annarita Ierardi Filip Novotný Gor Oganesyan Biswajit Banerjee Dimitrios Giannios Sergey Karpov Martin Topinka Elias Kammoun Jan Štrobl Alberto J. Castro-Tirado 10.1051/0004-6361/202659667 http://arxiv.org/abs/2603.05112v1 2026-03-05T12:30:51Z

Altermagnetism has recently emerged as a new class of spin compensated magnetic materials that exhibit momentum dependent spin splitting despite having zero net magnetization. The origin of these electronic signatures lies in symmetry operations that connect opposite spin sublattices while allowing spin splitting in momentum space. While most candidate materials identified so far belong to inorganic crystals with fixed lattice symmetries, the realization of altermagnetism ultimately requires platforms in which magnetic symmetry can be deliberately engineered. In this Perspective, we discuss how metal-organic frameworks (MOFs) provide a unique chemical platform to address this challenge. We first place altermagnetism in the broader context of magnetic and electronically active metal-organic networks, highlighting how reticular chemistry enables precise control over lattice geometry, dimensionality and electronic structure. We then discuss how these features position framework materials as promising candidates for realizing altermagnetism and highlight the key challenges that must be addressed to translate theoretical proposals into experimentally accessible systems. Finally, we critically assess current experimental challenges and outline emerging directions for realizing and controlling altermagnetism in coordination framework materials, which emerge as a versatile and powerful platform for exploring new paradigms in spintronics.

2026-03-05T12:30:51Z Diego López-Alcalá Andrei Shumilin José J. Baldoví 10.1021/jacs.6c06455 http://arxiv.org/abs/2601.19837v2 2026-04-14T04:56:59Z

European digital identity initiatives are grounded in regulatory frameworks designed to ensure interoperability and robust, harmonized security standards. The evolution of these frameworks culminates in eIDAS 2.0, whose origins trace back to the Electronic Signatures Directive 1999/93/EC, the first EU-wide legal foundation for the use of electronic signatures in cross-border electronic transactions. As technological capabilities advanced, the initial eIDAS 1.0 framework was increasingly criticized for its limitations and lack of comprehensiveness. Emerging decentralized approaches further exposed these shortcomings and introduced the possibility of integrating innovative identity paradigms, such as Self-Sovereign Identity (SSI) models. In this article, we contribute to the ongoing legal and policy debate on the European Digital Identity Framework by analyzing key provisions of eIDAS 2.0 and its accompanying recitals, drawing on a systematic literature review guided by defined Research Questions (RQ). This work employs a structured methodological approach that combines descriptive and comparative analysis, systematic gap analysis supported by a defined scoring matrix, and normative analysis to evaluate the compatibility of SSI properties with eIDAS 2.0 regulation, as operationalized via its Architecture and Reference Framework (ARF). Furthermore, we assess the ARF's guidelines and examine the extent to which it aligns with SSI. The analysis adopts a complementary perspective demonstrating how the regulation can be further developed to better support SSI in the future by identifying existing limitations and potential adoption opportunities within the current legal foundations of the framework.

2026-01-27T17:43:48Z Nacereddine Sitouah Marco Esposito Francesco Bruschi http://arxiv.org/abs/2601.06554v1 2026-01-10T12:47:44Z

FIDO2 and the WebAuthn standard offer phishing-resistant, public-key based authentication but traditionally rely on device-bound cryptographic keys that are not naturally portable across user devices. Recent passkey deployments address this limitation by enabling multi-device credentials synchronized via platform-specific cloud ecosystems. However, these approaches require users and organizations to trust the corresponding cloud or phone providers with the protection and availability of their authentication material. In parallel, qualified electronic signature (QES) tokens and smart-card--based PKCS#11 modules provide high-assurance, hardware-rooted identity, yet they are not directly compatible with WebAuthn flows. This paper explores architectural options for bridging these technologies by securing a virtual FIDO2 authenticator with a QES-grade PKCS#11 key and enabling encrypted cloud synchronization of FIDO2 private keys. We first present and implement a baseline architecture in which the cloud stores only ciphertext and the decryption capability remains anchored exclusively in the user's hardware token. We then propose a hardened variant that introduces an Oblivious Pseudorandom Function (OPRF)-based mechanism bound to a local user-verification factor, thereby mitigating cross-protocol misuse and ensuring that synchronization keys cannot be repurposed outside the intended FIDO2 semantics; this enhanced design is analyzed but not implemented. Both architectures preserve a pure WebAuthn/FIDO2 interface to relying parties while offering different trust and deployment trade-offs. We provide the system model, threat analysis, implementation of the baseline architecture, and experimental evaluation, followed by a discussion of the hardened variant's security implications for high-assurance authentication deployments.

2026-01-10T12:47:44Z 11 pages, 2 figures Kemal Bicakci Fatih Mehmet Varli Muhammet Emir Korkmaz Yusuf Uzunay http://arxiv.org/abs/2512.17867v1 2025-12-19T18:17:08Z

We carry out temperature-dependent scanning tunneling microscopy (STM) studies of the charge density wave (CDW) compound ZrTe$_3$ which is intentionally doped with Hf. Previous bulk studies tie Hf doping to an enhancement of the CDW transition temperature (T$_{CDW}$). In our work, by combining STM measurements with density functional theory (DFT) calculations, we observe and identify multiple defects in Zr$_{0.95}$Hf$_{0.05}$Te$_3$. Surprisingly, instead of finding clear structural or electronic signatures associated with Hf dopants, we determine the origin of the observed defects are consistent with Te and Zr vacancies. Further, our temperature dependent STM measurements allow us to examine CDW pinning to both types of observed defects below and above T$_{CDW}$.

2025-12-19T18:17:08Z Ghilles Ainouche Resmi Sudheer Susree Mohapatra Boning Yu Muhammad Suhayb Malik Yu Liu Cedomir Petrovic Abhilash Ravikumar Michael C. Boyer