Article
Materials Science, Multidisciplinary
Alexander Churkin, Shlomi Matityahu, Andrii O. Maksymov, Alexander L. Burin, Moshe Schechter
Summary: Tunneling two-level systems (TLS) prevalent in amorphous solids determine the low-temperature properties and dominate noise and decoherence in quantum nanodevices. Experimental deviations from the standard tunneling model suggest the necessity of a more precise model for describing TLSs. The temperature dependence of various physical properties can be explained by an energy-dependent TLS density of states reduced at low energies due to TLS-TLS interactions.
Article
Multidisciplinary Sciences
Pragya Shukla
Summary: This study provides a theoretical explanation for the qualitative universality of the ultrasonic attenuation coefficient at low temperatures by modeling and experimental observations of intermolecular interactions in amorphous systems.
SCIENTIFIC REPORTS
(2022)
Article
Materials Science, Multidisciplinary
M. Molina-Ruiz, H. C. Jacks, D. R. Queen, T. H. Metcalf, X. Liu, F. Hellman
Summary: Specific heat measurements of hydrogenated amorphous silicon prepared by hot-wire chemical vapor deposition reveal a large density of two-level systems at low temperature. Annealing at 200 degrees C irreversibly reduces the non-Debye specific heat by an order of magnitude at 2 K, indicating a significant reduction in the density of two-level systems. The presence of hydrogen is suggested to anomalously lower the coupling constant value.
Article
Materials Science, Ceramics
V. L. O. Freitas, S. S. Costa, C. J. Pacheco, B. P. Alho, P. O. Ribeiro, P. J. von Ranke, V. S. R. de Sousa, E. P. Nobrega
Summary: This study investigates the magnetic and magnetocaloric properties of amorphous alloys formed by the Gd55FexAl45-x series. A theoretical model based on Handrich's approximation is proposed to study the systems, aiming to understand the impact of Fe substitution for Al on magnetism and magnetocaloric effect. Through experimental and theoretical analysis, the physical mechanisms involved in the ferrimagnetic transitions of these amorphous alloys are explored.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2021)
Article
Materials Science, Multidisciplinary
H. C. Jacks, M. Molina-Ruiz, M. H. Weber, J. J. Maldonis, P. M. Voyles, M. R. Abernathy, T. H. Metcalf, X. Liu, F. Hellman
Summary: Amorphous silicon films prepared by electron-beam evaporation exhibit higher atomic density under specific conditions, and various spectroscopic techniques are used to analyze atomic disorder, local strains, dangling bonds, and nanovoids. The density variations are primarily attributed to the presence of nanovoids rather than within the network.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Chemistry, Physical
Mahboob Ali, Sevi Murugavel
Summary: We investigated the polaronic conduction mechanism in transition-metal phosphate with different crystallite sizes using broadband ac conductivity measurements. The conductivity spectra showed a frequency-independent dc conductivity at low frequencies, which became frequency-dependent above a certain frequency. The temperature-dependent dc conductivity was analyzed using Mott's model of polaronic conduction, which exhibited non-Arrhenius behavior within the hopping conduction region. At high temperatures, the dc conductivity was primarily determined by the polaron concentration, which varied with temperature.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Physics, Fluids & Plasmas
Bhanu Prasad Bhowmik, Michael Moshe, Itamar Procaccia
Summary: Recent progress in studying the physics of amorphous solids has shown that mechanical strains can be strongly screened by quadrupolar plastic events. This study provides direct measurements of the dipole field and demonstrates detailed agreement with the proposed theory. Measurements of the dipole fields can pinpoint the theory parameters that determine the profile of the displacement field.
Article
Materials Science, Multidisciplinary
Anthony E. Phillips, Matteo Baggioli, Timothy W. Sirk, Kostya Trachenko, Alessio Zaccone
Summary: The theory presents a comprehensive explanation of the viscoelasticity of amorphous media, considering the effects of confinement in one spatial dimension. The confinement-induced size effects are accounted for through the nonaffine contribution to the shear storage modulus, which is written as a sum over modes in k-space. The rigorous argument based on the analysis of the k-space integral shows that confinement size in one spatial dimension leads to an infrared cutoff for the modes contributing to the nonaffine correction to the modulus.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Qi Sun, Chunyi Zhao, Zixi Yin, Shiping Wang, Jing Leng, Wenming Tian, Shengye Jin
Summary: Contrary to theoretical predictions, ultrafast and highly efficient internal exciton dissociation was discovered in 2D lead halide perovskites, attributed to exciton-polarons formation and reduced exciton binding energy by polaronic screening. This unique property limits photoluminescence but explains exceptional performance in photovoltaic devices, offering insights for rational applications in light emitting and photovoltaics within the 2D hybrid perovskite family.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Xin-Yuan Gao, Hai-Yao Deng, Chun-Shing Lee, J. Q. You, Chi-Hang Lam
Summary: Using a lattice model based on void-induced dynamics, researchers were able to reproduce the linear relationship between heat capacity and temperature at very low temperatures. The results show that the heat capacity is dominated by two-level systems formed due to the localization of voids to neighboring sites. This supports the conventional two-level tunneling picture and provides a unified framework for understanding the microscopic dynamics of glasses at different temperatures.
Article
Materials Science, Multidisciplinary
M. Molina-Ruiz, Y. J. Rosen, H. C. Jacks, M. R. Abernathy, T. H. Metcalf, X. Liu, J. L. DuBois, F. Hellman
Summary: Amorphous silicon contains tunneling two-level systems that are the dominant energy loss mechanisms at low temperatures, affecting mechanical and electromagnetic oscillators by producing thermal and electromagnetic noise and energy loss. Mechanical loss correlates with atomic density, while dielectric loss correlates with dangling-bond density in amorphous silicon, suggesting different origins for these two energy dissipation processes.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Physics, Multidisciplinary
Prasenjit Das, Itamar Procaccia
Summary: It has been established that low frequency quasilocalized modes of amorphous solids at zero temperature exhibit universal density of states, possibly extending to finite temperatures. Research shows that well quenched model glasses at temperatures as high as T-g/3 possess the same universal density of states, as long as average particle positions stabilize before thermal diffusion destroys the cage structure of the material. The universal density of quasilocalized low frequency modes refers to vibrations around the thermally averaged configuration of the material.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Physical
Jun Jiang, Alec S. Mishkin, Kiran Prasai, Rui Zhang, Maher Yazback, Riccardo Bassiri, Martin M. Fejer, Hai-Ping Cheng
Summary: In this study, the energy landscape of ZrO2-doped amorphous Ta2O5 was explored through molecular dynamic simulations. It was found that TLS with low asymmetry and large elastic coupling constants, termed as "bad actors," contribute the most to mechanical loss. The concept of the oxygen cage was introduced to describe the local structural environment surrounding a metal ion, enabling a pictorial interpretation to distinguish two types of TLS. Additionally, the study revealed that non-cage-breaking TLS transitions contribute to the low-temperature mechanical loss peak near 40 K, while cage-breaking TLS transitions contribute to the second loss peak near 120 K.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Physics, Fluids & Plasmas
Anael Lemaitre, Chandana Mondal, Michael Moshe, Itamar Procaccia, Saikat Roy, Keren Screiber-Re'em
Summary: This study explores the plastic response and screened elasticity effects in amorphous solids under small external strains. The presence of plastic quadrupoles, dipoles, and monopoles is found to affect the elastic moduli, with predictions for qualitative changes at different quadrupole densities. Anomalous elasticity is shown to be richer than electrostatics due to the additional screening mode that exists.
Article
Physics, Multidisciplinary
A. Churkin, I. Gabdank, A. L. Burin, M. Schechter
Summary: Many disordered lattices exhibit universality in their low-temperature properties, similar to amorphous solids. In this paper, a two-TLS model based on the characteristics of disordered lattices is derived, explaining the quantitative universality of phonon attenuation and the energy scale at which it is observed. Analytical and numerical calculations of the densities of states (DOS) of weakly and strongly interacting TLSs show that the former follows a Gaussian function while the latter has a power-law correlation gap at low energies. These results suggest that weakly interacting t-TLSs are responsible for the standard low-temperature glassy physics, while the power-law DOS of S-TLSs can deviate from the universal behavior and be experimentally tested. The findings also apply to electronic and nuclear spins, indicating a reduced spin flip rate at temperatures below the hyperfine interaction magnitude.
EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS
(2023)
Article
Physics, Multidisciplinary
A. Bohrdt, Y. Wang, J. Koepsell, M. Kanasz-Nagy, E. Demler, F. Grusdt
Summary: The study reveals strong non-Gaussian correlations in doped quantum antiferromagnets and shows that higher-order correlations dominate over lower-order terms. By analyzing fifth-order spin-charge correlations in the t - J model, the research sheds light on the mobility of dopants and contrasts the results to predictions using models based on doped quantum spin liquids. These predictions can be tested in quantum simulators of the 2D Fermi-Hubbard model, offering insight into the microscopic nature of charge carriers in the Hubbard model relevant to high-T-c superconductivity.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Zhoushen Huang, Aashish Clerk, Ivar Martin
Summary: In a one-dimensional translationally invariant tight binding chain, non-dispersing wave packets can be realized as Floquet eigenstates using a spatially inhomogeneous drive, with their round-trip time locking at rational ratios of the driving period. Different wave packets with different ratios can coexist and travel at different speeds. Reverse engineering a drive protocol can reproduce a target Floquet micromotion, opening up new possibilities for Floquet engineering in quantum information sciences.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Yuto Ashida, Atac Imamoglu, Eugene Demler
Summary: This study proposes a nonperturbative approach to analyze correlations in quantum light-matter systems at strong coupling, achieving decoupling of light and matter degrees of freedom through a unitary transformation. It demonstrates the versatility of the method by applying it to specific models and discusses a generalization to spatially varying electromagnetic modes.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Kai Klocke, David Aasen, Roger S. K. Mong, Eugene A. Demler, Jason Alicea
Summary: This research introduces a time-domain probing method for the edge and quasiparticle content of non-Abelian spin liquids, utilizing ancillary quantum spins to reveal edge-state velocity and detect individual non-Abelian anyons and emergent fermions in suitable geometries. Anticipated applications include various topological phases in solid-state and cold-atoms settings.
PHYSICAL REVIEW LETTERS
(2021)
Article
Multidisciplinary Sciences
Cole Miles, Annabelle Bohrdt, Ruihan Wu, Christie Chiu, Muqing Xu, Geoffrey Ji, Markus Greiner, Kilian Q. Weinberger, Eugene Demler, Eun-Ah Kim
Summary: The study revealed that machine learning models can identify fourth-order spin-charge correlators as distinguishing features, shedding light on the Fermi-Hubbard model.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Multidisciplinary
A. Bohrdt, E. Demler, F. Grusdt
Summary: This study introduces a rotational variant of ARPES spectroscopy and identifies long-lived rotational resonances for individual dopants, which are interpreted as direct indicators of the microscopic structure of spinon-chargon bound states. By establishing a linear dependence of rotational energy on superexchange coupling, researchers explore emergent universal features of strongly correlated electron systems.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Alfred Zong, Pavel E. Dolgirev, Anshul Kogar, Yifan Su, Xiaozhe Shen, Joshua A. W. Straquadine, Xirui Wang, Duan Luo, Michael E. Kozina, Alexander H. Reid, Renkai Li, Jie Yang, Stephen P. Weathersby, Suji Park, Edbert J. Sie, Pablo Jarillo-Herrero, Ian R. Fisher, Xijie Wang, Eugene Demler, Nuh Gedik
Summary: Engineering novel states of matter with light is a cutting-edge area of materials research, with a focus on realizing broken-symmetry phases through ultrashort laser pulses. Experimental findings suggest that light-induced CDW consists solely of order parameter fluctuations, similar to critical fluctuations in equilibrium. These results indicate that materials with strong equilibrium fluctuations may host hidden orders after laser excitation.
PHYSICAL REVIEW LETTERS
(2021)
Article
Multidisciplinary Sciences
Joannis Koepsell, Dominik Bourgund, Pimonpan Sompet, Sarah Hirthe, Annabelle Bohrdt, Yao Wang, Fabian Grusdt, Eugene Demler, Guillaume Salomon, Christian Gross, Immanuel Bloch
Summary: The research reveals the competition between antiferromagnetism and hole motion in two-dimensional Mott insulators, as well as the transition from an anomalous metal to a conventional Fermi liquid with varying doping levels. Using a cold-atom quantum simulator, the transformation of multipoint correlations between spins and holes is observed to change with increasing doping, with the crossover completed around 30% hole doping. This work provides insights into theoretical approaches and potential connections to lower-temperature phenomena.
Article
Physics, Multidisciplinary
Pavel E. Dolgirev, Yi-Fan Qu, Mikhail B. Zvonarev, Tao Shi, Eugene Demler
Summary: The Fermi-polaron problem involves the interaction between a mobile impurity and a fermionic medium, with conventional expectations suggesting dissipative dynamics, but research in a one-dimensional system has revealed a different type of polaron dynamics.
Article
Physics, Multidisciplinary
J. Knoerzer, T. Shi, E. Demler, J. Cirac
Summary: By studying trapped-ion quantum systems, we can gain insights into generalized Holstein models and benchmark expensive numerical calculations. Our focus is on simulating many-electron systems and examining the competition between charge-density wave order, fermion pairing, and phase separation.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Fabian R. Geisenhof, Felix Winterer, Anna M. Seiler, Jakob Lenz, Ivar Martin, R. Thomas Weitz
Summary: In electrostatically-gapped bilayer graphene, topologically protected states can emerge at stacking domain walls even without a magnetic field. This study focuses on the interplay between these domain wall states and quantum Hall edge transport, finding that low magnetic fields maintain a constant conductance while high magnetic fields exhibit transport suppression.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
A. von Hoegen, M. Fechner, M. Foerst, N. Taherian, E. Rowe, A. Ribak, J. Porras, B. Keimer, M. Michael, E. Demler, A. Cavalleri
Summary: In this study, it is shown that certain lattice vibrations in cuprate high-T-c superconductors can induce transient terahertz reflectivity features suggestive of nonequilibrium superconductivity above the critical temperature. Time-resolved measurements reveal a three-order-of-magnitude amplification of a 2.5-THz electronic mode in driven YBa2Cu3O6+x. Theoretical analysis explains these observations by proposing an amplification mechanism for finite-momentum Josephson plasma polaritons. The study also emphasizes the significance of nonlinear mode mixing in amplifying fluctuating modes above the transition temperature in a wide range of materials.
Article
Physics, Multidisciplinary
Kieran Bull, Andrew Hallam, Zlatko Papic, Ivar Martin
Summary: This study investigates the possibility of a continuous time crystal (CTC) in undriven, energy-conserving systems and introduces a long-range XYZ spin model to describe CTC and QMBS. The dynamical phase diagram is mapped out through numerical simulations, identifying a regime where QMBS and CTC order coexist.
PHYSICAL REVIEW LETTERS
(2022)
Article
Quantum Science & Technology
Ehud Altman, Kenneth R. Brown, Giuseppe Carleo, Lincoln D. Carr, Eugene Demler, Cheng Chin, Brian DeMarco, Sophia E. Economou, Mark A. Eriksson, Kai-Mei C. Fu, Markus Greiner, Kaden R. A. Hazzard, Randall G. Hulet, Alicia J. Kollar, Benjamin L. Lev, Mikhail D. Lukin, Ruichao Ma, Xiao Mi, Shashank Misra, Christopher Monroe, Kater Murch, Zaira Nazario, Kang-Kuen Ni, Andrew C. Potter, Pedram Roushan, Mark Saffman, Monika Schleier-Smith, Irfan Siddiqi, Raymond Simmonds, Meenakshi Singh, I. B. Spielman, Kristan Temme, David S. Weiss, Jelena Vuckovic, Vladan Vuletic, Jun Ye, Martin Zwierlein
Summary: Quantum simulators are a rapidly developing technology that utilizes entanglement and many-particle behavior to explore and solve scientific, engineering, and computational problems. With over 300 quantum simulators in operation worldwide, recent advances promise a golden age of quantum simulators that have the potential to address societal challenges and draw from various fields of study. Investment in a national quantum simulator program is seen as crucial to advancing this field and realizing practical applications of quantum machines.
Article
Materials Science, Multidisciplinary
Dries Sels, Eugene Demler
Summary: Quantum phase estimation is utilized to compute the dynamical response functions of many-body quantum systems efficiently in polynomial time, by designing a circuit as a quantum generative model for high rank observables. The algorithm, requiring doubling the number of qubits compared to a simple analog simulator, can provide samples out of experimentally relevant spectra with logarithmic overhead.