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Non-Inertial Quantum Clock Frames Lead To Non-Hermitian Dynamics, Ismael L. Paiva, Amit Te'eni, Bar Y. Peled, Eliahu Cohen, Yakir Aharonov

Mathematics, Physics, and Computer Science Faculty Articles and Research

The operational approach to time is a cornerstone of relativistic theories, as evidenced by the notion of proper time. In standard quantum mechanics, however, time is an external parameter. Recently, many attempts have been made to extend the notion of proper time to quantum mechanics within a relational framework. Here, we use similar ideas combined with the relativistic mass-energy equivalence to study an accelerating massive quantum particle with an internal clock system. We show that the ensuing evolution from the perspective of the particle’s internal clock is non-Hermitian. This result does not rely on specific implementations of the clock. As …

Cold Atoms In Space: Community Workshop Summary And Proposed Road-Map, Iván Alonso, Cristiano Alpigiani, Brett David Altschul, Henrique Araújo, Gianluigi Arduini, Jan Arlt, Leonardo Badurina, Antun Balaž, Satvika Bandarupally, Barry C. Barish, Michele Barone, Michele Barsanti, Steven Bass, Angelo Bassi, Baptiste Battelier, Charles F. A. Baynham, Quentin Beaufils, Aleksandar Belić, Joel Bergé, Jose Bernabeu, Et. Al.

Faculty Publications

We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. …

A Patient-Specific Algorithm For Lung Segmentation In Chest Radiographs, Manawaduge Supun De Silva, Barath Narayanan Narayanan, Russell C. Hardie

Electrical and Computer Engineering Faculty Publications

Lung segmentation plays an important role in computer-aided detection and diagnosis using chest radiographs (CRs). Currently, the U-Net and DeepLabv3+ convolutional neural network architectures are widely used to perform CR lung segmentation. To boost performance, ensemble methods are often used, whereby probability map outputs from several networks operating on the same input image are averaged. However, not all networks perform adequately for any specific patient image, even if the average network performance is good. To address this, we present a novel multi-network ensemble method that employs a selector network. The selector network evaluates the segmentation outputs from several networks; on …

Helium Nanodroplets As An Efficient Tool To Investigate Hydrogen Attachment To Alkali Cations, Siegfried Kollotzek, José Campos-Martínez, Massimiliano Bartolomei, Fernando Pirani, Lukas Tiefenthaler, Marta I. Hernández, Teresa Lázaro, Eva Zunzunegui-Bru, Tomás González-Lezana, José Bretón, Javier Hernández-Rojas, Olof E. Echt, Paul Scheier

Faculty Publications

We report a novel method to reversibly attach and detach hydrogen molecules to positively charged sodium clusters formed inside a helium nanodroplet host matrix. It is based on the controlled production of multiply charged helium droplets which, after picking up sodium atoms and exposure to H₂ vapor, lead to the formation of Na_m⁺(H₂)_n clusters, whose population was accurately measured using a time-of-flight mass spectrometer. The mass spectra reveal particularly favorable Na⁺(H₂)_n and Na₂⁺(H₂)_n clusters for specific “magic” numbers of attached hydrogen molecules. …

Electromagnetism In Quark Matter At Intermediate Densities, Efrain J. Ferrer

Physics & Astronomy Faculty Publications

Several anomalous electromagnetic effects that can take place in quark matter at low temperatures and intermediate densities will be discussed. The anomalous transport properties of the spatially inhomogeneous phase of quark matter known as the Magnetic Dual Chiral Density Wave (MDCDW) phase will be reviewed. Going beyond mean-field approximation, it will be shown how linearly polarized electromagnetic waves that penetrate the MDCDW medium mix with the phonon fluctuations to give rise to two hybridized modes of propagation called axion polaritons. Finally, some possible implications of these results for the astrophysics of neutron stars will be indicated.

Design And Fabrication Of A Low-Cost Dip Coating System For Depositing Homogeneous And Transparent Zno Thin Films, Asaad S. Yasir, Basheer M. Hussein, Ammar S. Hameed, Noor J. Ridha, Firas K. Mohamad Alosfur, Khawla J. Tahir, Rajaa A. Madlol

Al-Bahir

ZnO has a resistivity of up to 104 Ω cm-1 in most cases. Nevertheless, by increasing the layer thickness, the resistivity decreases as well, resulting in greater current transport. The dip coating system was developed to prepare the ultra-thin film, it relied on a controller, stepper motor and some low-cost recycled materials. Thin films of ZnO were successfully deposited on indium tin oxide substrates. The effects of the dipping cycles were investigated. Dipping processes were applied several times (1, 2, and 3) for the same concentrations (0.1) M to obtain homogeneous thin films. X-ray diffraction showed that the structure of …

Resolving Galactic Binaries Using A Network Of Space-Borne Gravitational Wave Detectors, Xue-Hao Zhang, Shao-Dong Zhao, Soumya D. Mohanty, Yu-Xiao Liu

Physics & Astronomy Faculty Publications

Extracting gravitational wave (GW) signals from individual Galactic binaries (GBs) against their self-generated confusion noise is a key data analysis challenge for space-borne detectors operating in the ≈0.1 to ≈10  mHz range. Given the likely prospect that there will be multiple such detectors, namely Laser Interferometer Space Antenna (LISA), Taiji, and Tianqin, with overlapping operational periods in the next decade, it is important to examine the extent to which the joint analysis of their data can benefit GB resolution and parameter estimation. To investigate this, we use realistic simulated LISA and Taiji data containing the set of 30×106 GBs used …

Investigation Of Laser And Nonlinear Properties Of Anderson Localizing Optical Fibers, Cody Ryan Bassett

Optical Science and Engineering ETDs

In this dissertation, I investigate the possibility of lasing and nonlinear phenomena in completely solid-state transverse Anderson localizing optical fibers (TALOFs). I examine three areas within this range of topics. The research in nonlinear phenomena focuses on four-wave mixing (FWM). FWM is of high interest in TALOFs due to the fact that guided localized modes of the fiber each have different propagation constants, and thus unique possible FWM pairs can be generated from the same input pump beam. I demonstrate the generation of FWM in the TALOF by pumping it with 532 nm light into a localized mode and observing …

Search For New Particles In An Extended Higgs Sector With Four Bquarks In The Final State At √S=13tev, Cms Collaboration

Department of Physics and Astronomy: Faculty Publications

A search for a massive resonance X decaying to a pair of spin-0 bosons φ that themselves decay to pairs of bottom quarks, is presented. The analysis is restricted to the mass ranges m_φ from 25 to 100GeVand m_X from 1 to 3TeV. For these mass ranges, the decay products of each φ boson are expected to merge into a single large-radius jet. Jet substructure and flavor identification techniques are used to identify these jets. The search is based on CERN LHC proton-proton collision data at √s=13 TeV, collected with the CMS detector in 2016–2018, corresponding to an …

Transition-Metal Ions In Β-Ga2O3 Crystals: Identification Of Ni Acceptors, Timothy D. Gustafson, Nancy C. Giles, Brian C. Holloway, J. Jesenovec, B. L. Dutton, M. D. Mccluskey, Larry E. Halliburton

Faculty Publications

Excerpt: Transition-metal ions (Ni, Cu, and Zn) in β-Ga₂O₃ crystals form deep acceptor levels in the lower half of the bandgap. In the present study, we characterize the Ni acceptors in a Czochralski-grown crystal and find that their (0/−) level is approximately 1.40 eV above the maximum of the valence band.

Evaluating Accuracy Of Solar Ground Station System Data, Emad Jaleel Mahdi, Ali K. Resen, Ahmed B. Khamees, Mudar Ahmed Abdulsattar

Karbala International Journal of Modern Science

The solar radiation data is crucial for many solar applications. In this regard, this manuscript analyzed and compared the correctness of ground station data with data from the PVGIS. Empirical equations were adopted to build software. This software calculates the global, direct, diffuse, and rates of solar radiation data on two axes. The result of the analysis was employed to assess the compatibility, dependability, and confidence of these types of data. The comparison showed that vastly variations in some curves from dawn to sunset. In sum, every site exhibit variation in solar radiation station rates. These results could serve as …

Submillimeter-Wave Cornea Phantom Sensing Over An Extended Depth Of Field With An Axicon-Generated Bessel Beam, Mariangela Baggio, Aleksi Tamminen, Joel Lamberg, Roman Grigorev, Samu-Ville Pälli, Juha Ala-Laurinaho, Irina Nefedova, Jean-Louis Bourges, Sophie X. Deng, Elliott R. Brown, Vincent P. Wallace, Zachary D. Taylor

Physics Faculty Publications

The feasibility of a 220 - 330 GHz zero order axicon generated Bessel beam for corneal water content was explored. Simulation and experimental data from the 25-degree cone angle hyperbolic-axicon lens illuminating metallic spherical targets demonstrate a monotonically decreasing, band integrated, backscatter intensity for increasing radius of curvature from 7 - 11 mm, when lens reflector and optical axis are aligned. Further, for radii >= 9.5 mm, maximum signal was obtained with a 1 mm transverse displacement between lens and reflector optical axes arising from spatial correlation between main lobe and out of phase side lobes. Thickness and permittivity parameter …

Plasmon Damping Rates In Coulomb-Coupled 2d Layers In A Heterostructure, Dipendra Dahal, Godfrey Gumbs, Andrii Iurov, Chin-Sen Ting

Publications and Research

The Coulomb excitations of charge density oscillation are calculated for a double-layer heterostructure. Specifically, we consider two-dimensional (2D) layers of silicene and graphene on a substrate. From the obtained surface response function, we calculated the plasmon dispersion relations, which demonstrate how the Coulomb interaction renormalizes the plasmon frequencies. Most importantly, we have conducted a thorough investigation of how the decay rates of the plasmons in these heterostructures are affected by the Coulomb coupling between different types of two- dimensional materials whose separations could be varied. A novel effect of nullification of the silicene band gap is noticed when graphene is …

Surface Versus Bulk State Transitions In Inkjet-Printed All-Inorganic Perovskite Quantum Dot Films, Thilini K. Ekanayaka, Dylan Richmond, Mason Mccormick, Shashank R. Nandyala, Halle C. Helfrich, Alexander Sinitskii, Jon M. Pikal, Carolina C. Ilie, Peter A. Dowben, Andrew J. Yost

Department of Physics and Astronomy: Faculty Publications

The anion exchange of the halides, Br and I, is demonstrated through the direct mixing of two pure perovskite quantum dot solutions, CsPbBr₃ and CsPbI₃, and is shown to be both facile and result in a completely alloyed single phase mixed halide perovskite. Anion exchange is also observed in an interlayer printing method utilizing the pure, unalloyed perovskite solutions and a commercial inkjet printer. The halide exchange was confirmed by optical absorption spectroscopy, photoluminescent spectroscopy, X-ray diffraction, and X-ray photoemission spectroscopy characterization and indicates that alloying is thermodynamically favorable, while the formation of a clustered alloy is …

Core-Collapse Supernova Constraint On The Origin Of Sterile Neutrino Dark Matter Via Neutrino Self-Interactions, Yu-Ming Chen, Manibrata Sen, Walter Tangarife, Douglas Tuckler, Yue Zhang

Physics: Faculty Publications and Other Works

Novel neutrino self-interaction can open up viable parameter space for the relic abundance of sterile-neutrino dark matter (SvDM). In this work, we constrain the relic target using core-collapse supernova which features the same fundamental process and a similar environment to the early universe era when SvDM is dominantly produced. We present a detailed calculation of the effects of a massive scalar mediated neutrino self-interaction on the supernova cooling rate, including the derivation of the thermal potential in the presence of non-zero chemical potentials from plasma species. Our results demonstrate that the supernova cooling argument can cover …

Sars-Cov-2 Spike Conformation Determines Plasma Neutralizing Activity Elicited By A Wide Panel Of Human Vaccines, John E. Bowen, Young-Jun Park, Cameron Stewart, Jack T. Brown, William K. Sharkey, Alexandra C. Walls, Anshu Joshi, Kumail Ahmed, Asefa Shariq, Najeeha Talat Iqbal

Department of Paediatrics and Child Health

Numerous safe and effective coronavirus disease 2019 vaccines have been developed worldwide that use various delivery technologies and engineering strategies. We show here that vaccines containing prefusion-stabilizing S mutations elicit antibody responses in humans with enhanced recognition of S and the S1 subunit relative to postfusion S as compared with vaccines lacking these mutations or natural infection. Prefusion S and S1 antibody binding titers positively and equivalently correlated with neutralizing activity, and depletion of S1-directed antibodies completely abrogated plasma neutralizing activity. We show that neutralizing activity is almost entirely directed to the S1 subunit and that variant cross-neutralization is mediated …

Misfit-Generated Structural And Optical Anisotropies Of The Natural Mos2-Pbs Van Der Waals Heterostructure Merelaniite, Luca Bindi, Arindam Dasgupta, Pinaki Mukherjee, Jie Gao, Xiaodong Yang, John Jaszczak

Michigan Tech Publications, Part 1

Significant efforts developing MoS2-PbS-based heterostructure devices with several different architectures show promise for photosensor, solar cell, and chemical sensor applications. Merelaniite (Mo4Pb4VSbS15) is a newly discovered natural van der Waals heterostructure of the cylindrite type, composed predominantly of heavily modulated pseudotetragonal PbS layers and pseudohexagonal MoS2 layers with large misfit-induced anisotropy. For an incommensurate modulated structure, the refined structural model from single-crystal x-ray diffraction analysis is in reasonable agreement with the results obtained by high-resolution scanning transmission electron microscopy, especially in light of the fact that that the two isolated single-crystal domains used for the x-ray and electron diffraction experiments …

Refining The Masses And Radii Of The Star Kepler-33 And Its Five Transiting Planets, James Sikora, Jason Rowe, Daniel Jontof-Hutter, Jack J. Lissauer

Pacific Faculty Work

Kepler-33 hosts five validated transiting planets ranging in period from 5 to 41 days. The planets are in nearly coplanar orbits and exhibit remarkably similar (appropriately scaled) transit durations indicative of similar impact parameters. The outer three planets have a radius of 3.5 ≲ R p/R ⊕ ≲ 4.7 and are closely packed dynamically, and thus transit timing variations can be observed. Photodynamical analysis of transit timing variations provide 2σ upper bounds on the eccentricity of the orbiting planets (ranging from <0.02 to <0.2) and the mean density of the host star ( 0.39 − 0.02 + 0.01 g cm − 3 ). We combine Gaia Early Data Release 3 parallax observations, the previously reported host-star effective temperature and metallicity, and our photodynamical model to refine properties of the host star and the transiting planets. Our analysis yields well-constrained masses for Kepler-33 e ( 6.6 − 1.0 + 1.1 M ⊕ ) and f ( 8.2 − 1.2 + 1.6 M ⊕ ) along with 2σ upper limits for planets c (<19 M ⊕) and d (<8.2 M ⊕). We confirm the reported low bulk densities of planet d (<0.4 g cm⁻³), e (0.8 ± 0.1 g cm⁻³), and f (0.7 ± 0.1 g cm⁻³). …

General Relativity With Applications To Astrophysics / Relativistic Astrophysics, Chandrachur Chakraborty Dr.

Basic Science Collection

I'm currently working on the various aspects of the following research topics: (i) Lense-Thirring Effect in strong gravitational fields, Spin precession, Black hole/Naked singularity shadow ; (ii) Theoretical aspects & the corresponding observational implications of Kerr black holes/naked singularities, Kerr-Taub-NUT spacetime & Gravitomagnetic monopole theory, Neutron star, Wormholes (iii) Gravitational waves (theory), Analogue Models of Gravity (iv) High energy astrophysical phenomena: Relativistic accretion, Tilted accretion disc, Bardeen-Petterson effect, Quasi-periodic-oscillations, Relativistic jets, Blandford-Znajek mechanism, Magnetic Penrose process, Gravitational Faraday rotation.

1. https://journals.aps.org/prd/abstract/10.1103/PhysRevD.105.064072
2. https://www.mdpi.com/2218-1997/8/3/193
3. https://link.springer.com/article/10.1140/epjc/s10052-021-09696-3
4. https://journals.aps.org/prd/abstract/10.1103/PhysRevD.98.043021

The C-Equivalence Principle And Its Implications For Physics, Max Tran

Publications and Research

The c-equivalence principle, commonly accepted as true by most physicists, is the unstated assumption that (1/sqrt(ε₀μ₀)) equals the kinematic speed of light. Should someone prove the principle false, it would render the composition of two Lorentz transformations meaningless. The second hypothesis of the Special Theory of Relativity in its strong form would also be invalidated. This paper examined some of the consequences for physics, should this principle be proven false and outline some experiments to determine light speed, which could falsify the principle and provide evidence for the ether.

Inertial Motion On The Earth's Spheroidal Surface, Boyd F. Edwards, Cade Pankey, John M. Edwards

All Physics Faculty Publications

As seen by an observer in the rotating frame, the earth’s small spheroidal deformations neutralize the centrifugal force, leaving only the smaller Coriolis force to govern the “inertial” motion of objects that move on its surface, assumed smooth and frictionless. Previous studies of inertial motion employ weakly spheroidal equations of motion that ignore the influence of the centrifugal force and yet treat the earth as a sphere. The latitude dependence of these equations renders them strongly nonlinear. We derive and justify these equations and use them to identify, classify, name, describe, and illustrate all possible classes of inertial motion, including …

Photoionization Energetics And Dissociation Pathways Of Hydroperoxyethyl Formate Produced In The Reaction Of Ch3Choo + Formic Acid, Vincent J. Esposito, Trent A. Mchenry, Marsha I. Lester

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The bimolecular reaction of Criegee intermediates, zwitterionic carbonyl oxide species produced in alkene ozonolysis, with organic acids leads to formation of functional hydroperoxides implicated in the generation of atmospheric aerosols. This theoretical study using high-level explicitly correlated coupled-cluster theory examines the low energy conformers of hydroperoxyethyl formate [HOOCH(CH₃)OCHO, HPEF] formed in the bimolecular reaction of CH₃CHOO, a simple alkyl-substituted Criegee intermediate, with formic acid, and the detection of HPEF via photoionization. The vertical and adiabatic ionization energies of HPEF are computed, along with the pathways for dissociative ionization that produce HO₂ or OCHO fragments with …