Scholarly Works, Department of PhysicsResearch articles, presentations, and other scholarshiphttp://hdl.handle.net/10919/242872020-10-20T21:14:56Z2020-10-20T21:14:56ZHiggs inflation, vacuum stability, and leptogenesisBarrie, Neil D.Sugamoto, AkioTakeuchi, TatsuYamashita, Kimikohttp://hdl.handle.net/10919/1002812020-10-07T07:21:15Z2020-08-17T00:00:00ZBarrie, Neil D.; Sugamoto, Akio; Takeuchi, Tatsu; Yamashita, Kimiko
2020-08-17T00:00:00ZWe consider the introduction of a complex scalar field carrying a global lepton number charge to the Standard Model and the Higgs inflation framework. The conditions are investigated under which this model can simultaneously ensure Higgs vacuum stability up to the Planck scale, successful inflation, non-thermal Leptogenesis via the pendulum mechanism, and light neutrino masses. These can be simultaneously achieved when the scalar lepton is minimally coupled to gravity, that is, when standard Higgs inflation and reheating proceed without the interference of the additional scalar degrees of freedom. If the scalar lepton also has a non-minimal coupling to gravity, a multi-field inflation scenario is induced, with interesting interplay between the successful inflation constraints and those from vacuum stability and Leptogenesis. The parameter region that can simultaneously achieve the above goals is explored.New constraints on heavy neutral leptons from Super-Kamiokande dataColoma, P.Hernandez, P.Munoz, V.Shoemaker, I. M.http://hdl.handle.net/10919/999432020-09-11T07:21:33Z2020-03-12T00:00:00ZColoma, P.; Hernandez, P.; Munoz, V.; Shoemaker, I. M.
2020-03-12T00:00:00ZHeavy neutral leptons are predicted in many extensions of the Standard Model with massive neutrinos. If kinematically accessible, they can be copiously produced from kaon and pion decays in atmospheric showers, and subsequently decay inside large neutrino detectors. We perform a search for these long-lived particles using Super-Kamiokande multi-GeV neutrino data and derive stringent limits on the mixing with electron, muon and tau neutrinos as a function of the long-lived particle mass. We also present the limits on the branching ratio versus lifetime plane, which are helpful in determining the constraints in non-minimal models where the heavy neutral leptons have new interactions with the Standard Model.Modular curves and Mordell-Weil torsion in F-theoryHajouji, NadirOehlmann, Paul-Konstantinhttp://hdl.handle.net/10919/998672020-09-07T03:27:50Z2020-04-16T00:00:00ZHajouji, Nadir; Oehlmann, Paul-Konstantin
2020-04-16T00:00:00ZIn this work we prove a bound for the torsion in Mordell-Weil groups of smooth elliptically fibered Calabi-Yau 3- and 4-folds. In particular, we show that the set of torsion groups which can occur on a smooth elliptic Calabi-Yau n-fold is contained in the set of subgroups which appear on a rational elliptic surface if n >= 3 and is slightly larger for n = 2. The key idea in our proof is showing that any elliptic fibration with sufficiently large torsion(1) has singularities in codimension 2 which do not admit a crepant resolution. We prove this by explicitly constructing and studying maps to a modular curve whose existence is predicted by a universal property. We use the geometry of modular curves to explain the minimal singularities that appear on an elliptic fibration with prescribed torsion, and to determine the degree of the fundamental line bundle (hence the Kodaira dimension) of the universal elliptic surface which we show to be consistent with explicit Weierstrass models. The constraints from the modular curves are used to bound the fundamental group of any gauge group G in a supergravity theory obtained from F-theory. We comment on the isolated 8-dimensional theories, obtained from extremal K3's, that are able to circumvent lower dimensional bounds. These theories neither have a heterotic dual, nor can they be compactified to lower dimensional minimal SUGRA theories. We also comment on the maximal, discrete gauged symmetries obtained from certain Calabi-Yau threefold quotients.Numerical metrics, curvature expansions and Calabi-Yau manifoldsCui, WeiGray, Jameshttp://hdl.handle.net/10919/997282020-09-07T03:27:50Z2020-05-11T00:00:00ZCui, Wei; Gray, James
2020-05-11T00:00:00ZWe discuss the extent to which numerical techniques for computing approximations to Ricci-flat metrics can be used to investigate hierarchies of curvature scales on Calabi-Yau manifolds. Control of such hierarchies is integral to the validity of curvature expansions in string effective theories. Nevertheless, for seemingly generic points in moduli space it can be difficult to analytically determine if there might be a highly curved region localized somewhere on the Calabi-Yau manifold. We show that numerical techniques are rather efficient at deciding this issue.Exploring optimization strategies for improving explicit water models: Rigid n-point model and polarizable model based on Drude oscillatorXiong, YeyueOnufriev, Alexey V.http://hdl.handle.net/10919/995882020-10-09T18:13:00Z2019-11-14T00:00:00ZXiong, Yeyue; Onufriev, Alexey V.
2019-11-14T00:00:00ZRigid n-point water models are widely used in atomistic simulations, but have known accuracy drawbacks. Increasing the number of point charges, as well as adding electronic polarizability, are two common strategies for accuracy improvements. Both strategies come at considerable computational cost, which weighs heavily against modest possible accuracy improvements in practical simulations. In an effort to provide guidance for model development, here we have explored the limiting accuracy of “electrostatically globally optimal” npoint water models in terms of their ability to reproduce properties of water dimer—a mimic of the condensed state of water. For a given n, each model is built upon a set of reference multipole moments (e.g. ab initio) and then optimized to reproduce water dimer total dipole moment. The models are then evaluated with respect to the accuracy of reproducing the geometry of the water dimer. We find that global optimization of the charge distribution alone can deliver high accuracy of the water model: for n = 4 or n = 5, the geometry of the resulting water dimer can be almost within 50 of the ab initio reference, which is half that of the experimental error margin. Thus, global optimization of the charge distribution of classical n-point water models can lead to high accuracy models. We also find that while the accuracy improvement in going from n = 3 to n = 4 is substantial, the additional accuracy increase in going from n = 4 to n = 5 is marginal. Next, we have explored accuracy limitations of the standard practice of adding electronic polarizability (via a Drude particle) to a “rigid base”—pre-optimization rigid n-point water model. The resulting model (n = 3) shows a relatively small improvement in accuracy, suggesting that the strategy of merely adding the polarizability to an inferior accuracy water model used as the base cannot fix the defects of the latter. An alternative strategy in which the parameters of the rigid base model are globally optimized along with the polarizability parameter is much more promising: the resulting 3-point polarizable model out-performs even the 5-point optimal rigid model by a large margin. We suggest that future development efforts consider 3- and 4-point polarizable models where global optimization of the “rigid base” is coupled to optimization of the polarizability to deliver globally optimal solutions.Coherent Multispin Exchange Coupling in a Quantum-Dot Spin ChainQiao, HaifengKandel, Yadav P.Deng, KuangyinFallahi, SaeedGardner, Geoffrey C.Manfra, Michael J.Barnes, EdwinNichol, John M.http://hdl.handle.net/10919/994392020-09-07T03:27:50Z2020-07-08T00:00:00ZQiao, Haifeng; Kandel, Yadav P.; Deng, Kuangyin; Fallahi, Saeed; Gardner, Geoffrey C.; Manfra, Michael J.; Barnes, Edwin; Nichol, John M.
2020-07-08T00:00:00ZHeisenberg exchange coupling between neighboring electron spins in semiconductor quantum dots provides a powerful tool for quantum information processing and simulation. Although so far unrealized, extended Heisenberg spin chains can enable long-distance quantum information transfer and the generation of nonequilibrium quantum states. In this work, we implement simultaneous, coherent exchange coupling between all nearest-neighbor pairs of spins in a quadruple quantum dot. The main challenge in implementing simultaneous exchange couplings is the nonlinear and nonlocal dependence of the exchange couplings on gate voltages. Through a combination of electrostatic simulation and theoretical modeling, we show that this challenge arises primarily due to lateral shifts of the quantum dots during gate pulses. Building on this insight, we develop two models that can be used to predict the confinement gate voltages for a desired set of exchange couplings. Although the model parameters depend on the number of exchange couplings desired (suggesting that effects in addition to lateral wave-function shifts are important), the models are sufficient to enable simultaneous and independent control of all three exchange couplings in a quadruple quantum dot. We demonstrate two-, three-, and four-spin exchange oscillations, and our data agree with simulations.Reflections on the anomalous ANITA events: the Antarctic subsurface as a possible explanationShoemaker, Ian M.Kusenko, AlexanderMunneke, Peter KuipersRomero-Wolf, AndrewSchroeder, Dustin M.Siegert, Martin J.http://hdl.handle.net/10919/988172020-09-01T04:30:30Z2020-03-30T00:00:00ZShoemaker, Ian M.; Kusenko, Alexander; Munneke, Peter Kuipers; Romero-Wolf, Andrew; Schroeder, Dustin M.; Siegert, Martin J.
2020-03-30T00:00:00ZThe Antarctic Impulsive Transient Antenna (ANITA) balloon experiment was designed to detect radio signals initiated by high-energy neutrinos and cosmic ray (CR) air showers. These signals are typically discriminated by the polarization and phase inversions of the radio signal. The reflected signal from CRs suffer phase inversion compared to a direct ‘tau neutrino’ event. In this paper, we study subsurface reflection, which can occur without phase inversion, in the context of the two anomalous up-going events reported by ANITA. It is found that subsurface layers and firn density inversions may plausibly account for the events, while ice fabric layers and wind ablation crusts could also play a role. This hypothesis can be tested with radar surveying of the Antarctic region in the vicinity of the anomalous ANITA events. Future experiments should not use phase inversion as a sole criterion to discriminate between down-going and up-going events, unless the subsurface reflection properties are well understood.Non-equilibrium signal integration in hydrogelsKorevaar, Peter A.Kaplan, C. NadirGrinthal, AlisonRust, Reanne M.Aizenberg, Joannahttp://hdl.handle.net/10919/985312020-09-01T04:30:16Z2020-01-20T00:00:00ZKorevaar, Peter A.; Kaplan, C. Nadir; Grinthal, Alison; Rust, Reanne M.; Aizenberg, Joanna
2020-01-20T00:00:00ZMaterials that perform complex chemical signal processing are ubiquitous in living systems. Their synthetic analogs would transform developments in biomedicine, catalysis, and many other areas. By drawing inspiration from biological signaling dynamics, we show how simple hydrogels have a previously untapped capacity for non-equilibrium chemical signal processing and integration. Using a common polyacrylic acid hydrogel, with divalent cations and acid as representative stimuli, we demonstrate the emergence of non-monotonic osmosis-driven spikes and waves of expansion/contraction, as well as traveling color waves. These distinct responses emerge from different combinations of rates and sequences of arriving stimuli. A non-equilibrium continuum theory we developed quantitatively captures the non-monotonic osmosis-driven deformation waves and determines the onset of their emergence in terms of the input parameters. These results suggest that simple hydrogels, already built into numerous systems, have a much larger sensing space than currently employed.Efficient symmetry-preserving state preparation circuits for the variational quantum eigensolver algorithmGard, Bryan T.Zhu, LinghuaBarron, George S.Mayhall, Nicholas J.Economou, Sophia E.Barnes, Edwinhttp://hdl.handle.net/10919/985062020-08-23T03:43:22Z2020-01-28T00:00:00ZGard, Bryan T.; Zhu, Linghua; Barron, George S.; Mayhall, Nicholas J.; Economou, Sophia E.; Barnes, Edwin
2020-01-28T00:00:00ZThe variational quantum eigensolver is one of the most promising approaches for performing chemistry simulations using noisy intermediate-scale quantum (NISQ) processors. The efficiency of this algorithm depends crucially on the ability to prepare multiqubit trial states on the quantum processor that either include, or at least closely approximate, the actual energy eigenstates of the problem being simulated while avoiding states that have little overlap with them. Symmetries play a central role in determining the best trial states. Here, we present efficient state preparation circuits that respect particle number, total spin, spin projection, and time-reversal symmetries. These circuits contain the minimal number of variational parameters needed to fully span the appropriate symmetry subspace dictated by the chemistry problem while avoiding all irrelevant sectors of Hilbert space. We show how to construct these circuits for arbitrary numbers of orbitals, electrons, and spin quantum numbers, and we provide explicit decompositions and gate counts in terms of standard gate sets in each case. We test our circuits in quantum simulations of the H2 and LiH molecules and find that they outperform standard state preparation methods in terms of both accuracy and circuit depth.Constraints on flavor-diagonal non-standard neutrino interactions from Borexino Phase-IIAgarwalla, S. K.Agostini, M.Altenmueller, K.Appel, S.Atroshchenko, V.Bagdasarian, Z.Basilico, D.Bellini, G.Benziger, J.Bick, D.Bonfini, G.Bravo, D.Caccianiga, B.Calaprice, F.Caminata, A.Cappelli, L.Cavalcante, P.Cavanna, F.Chepurnov, A.Choi, K.D'Angelo, D.Davini, S.Derbin, A.Di Giacinto, A.Di Marcello, V.Ding, X. F.Di Ludovico, A.Di Noto, L.Drachnev, I.Fomenko, K.Formozov, A.Franco, D.Gabriele, F.Galbiati, C.Gschwender, M.Ghiano, C.Giammarchi, M.Goretti, A.Gromov, M.Guffanti, D.Hagner, C.Hungerford, Ed V.Ianni, AldoIanni, AndreaJany, A.Jeschke, D.Kumaran, S.Kobychev, VKorga, G.Lachenmaier, T.Laubenstein, M.Litvinovich, E.Lombardi, P.Ludhova, L.Lukyanchenko, G.Lukyanchenko, L.Machulin, I.ManuzioMarcocci, S.Maricic, J.Martyn, J.Meroni, E.Meyer, M.Miramonti, L.Misiaszek, M.Muratova, V.Neumair, B.Nieslony, M.Oberauer, L.Orekhov, V.Ortica, F.Pallavicini, M.Papp, L.Penek, O.Pietrofaccia, L.Pilipenko, N.Pocar, A.Raikov, G.Ranucci, G.Razeto, A.Re, A.Redchuk, M.Romani, A.Rossi, N.Rottenanger, S.Schoenert, S.Semenov, D.Skorokhvatov, M.Smirnov, O.Sotnikov, A.Sun, C.Suvorov, Y.Takeuchi, T.Tartaglia, R.Testera, G.Thurn, J.Unzhakov, E.Vishneva, A.Vogelaar, R. Brucevon Feilitzsch, F.Wojcik, M.Wurm, M.Zaimidoroga, O.Zavatarelli, S.Zuber, K.Zuzel, G.http://hdl.handle.net/10919/984152020-09-25T12:33:49Z2020-02-05T00:00:00ZAgarwalla, S. K.; Agostini, M.; Altenmueller, K.; Appel, S.; Atroshchenko, V.; Bagdasarian, Z.; Basilico, D.; Bellini, G.; Benziger, J.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Calaprice, F.; Caminata, A.; Cappelli, L.; Cavalcante, P.; Cavanna, F.; Chepurnov, A.; Choi, K.; D'Angelo, D.; Davini, S.; Derbin, A.; Di Giacinto, A.; Di Marcello, V.; Ding, X. F.; Di Ludovico, A.; Di Noto, L.; Drachnev, I.; Fomenko, K.; Formozov, A.; Franco, D.; Gabriele, F.; Galbiati, C.; Gschwender, M.; Ghiano, C.; Giammarchi, M.; Goretti, A.; Gromov, M.; Guffanti, D.; Hagner, C.; Hungerford, Ed V.; Ianni, Aldo; Ianni, Andrea; Jany, A.; Jeschke, D.; Kumaran, S.; Kobychev, V; Korga, G.; Lachenmaier, T.; Laubenstein, M.; Litvinovich, E.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Lukyanchenko, L.; Machulin, I.; Manuzio; Marcocci, S.; Maricic, J.; Martyn, J.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Muratova, V.; Neumair, B.; Nieslony, M.; Oberauer, L.; Orekhov, V.; Ortica, F.; Pallavicini, M.; Papp, L.; Penek, O.; Pietrofaccia, L.; Pilipenko, N.; Pocar, A.; Raikov, G.; Ranucci, G.; Razeto, A.; Re, A.; Redchuk, M.; Romani, A.; Rossi, N.; Rottenanger, S.; Schoenert, S.; Semenov, D.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sun, C.; Suvorov, Y.; Takeuchi, T.; Tartaglia, R.; Testera, G.; Thurn, J.; Unzhakov, E.; Vishneva, A.; Vogelaar, R. Bruce; von Feilitzsch, F.; Wojcik, M.; Wurm, M.; Zaimidoroga, O.; Zavatarelli, S.; Zuber, K.; Zuzel, G.
2020-02-05T00:00:00ZThe Borexino detector measures solar neutrino fluxes via neutrino-electron elastic scattering. Observed spectra are determined by the solar-nu(e) survival probability P-ee(E), and the chiral couplings of the neutrino and electron. Some theories of physics beyond the Standard Model postulate the existence of Non-Standard Interactions (NSI's) which modify the chiral couplings and P-ee(E). In this paper, we search for such NSI's, in particular, flavor-diagonal neutral current interactions that modify the nu(e)e and nu(tau)e couplings using Borexino Phase II data. Standard Solar Model predictions of the solar neutrino fluxes for both high- and low-metallicity assumptions are considered. No indication of new physics is found at the level of sensitivity of the detector and constraints on the parameters of the NSI's are placed. In addition, with the same dataset the value of sin(2)theta(W) is obtained with a precision comparable to that achieved in reactor antineutrino experiments .