SwePub - sökning: WFRF:(Wilczek Frank)

Numrering	Referens	Omslagsbild	Hitta
1.	Morampudi, Siddhardh C., et al. (författare) Statistics of Fractionalized Excitations through Threshold Spectroscopy 2017 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 118:22 Tidskriftsartikel (refereegranskat)abstract We show that neutral anyonic excitations have a signature in spectroscopic measurements of materials: The low-energy onset of spectral functions near the threshold follows universal power laws with an exponent that depends only on the statistics of the anyons. This provides a route, using experimental techniques such as neutron scattering and tunneling spectroscopy, for detecting anyonic statistics in topologically ordered states such as gapped quantum spin liquids and hypothesized fractional Chern insulators. Our calculations also explain some recent theoretical results in spin systems.
2.	Agarwal, Girish, et al. (författare) Light, the universe and everything-12 Herculean tasks for quantum cowboys and black diamond skiers 2018 Ingår i: Journal of Modern Optics. - : Informa UK Limited. - 0950-0340 .- 1362-3044. ; 65:11, s. 1261-1308 Tidskriftsartikel (refereegranskat)abstract The Winter Colloquium on the Physics of Quantum Electronics (PQE) has been a seminal force in quantum optics and related areas since 1971. It is rather mind-boggling to recognize how the concepts presented at these conferences have transformed scientific understanding and human society. In January 2017, the participants of PQE were asked to consider the equally important prospects for the future, and to formulate a set of questions representing some of the greatest aspirations in this broad field. The result is this multi-authored paper, in which many of the world's leading experts address the following fundamental questions: (1) What is the future of gravitational wave astronomy? (2) Are there new quantum phases of matter away from equilibrium that can be found and exploited - such as the time crystal? (3) Quantum theory in uncharted territory: What can we learn? (4) What are the ultimate limits for laser photon energies? (5) What are the ultimate limits to temporal, spatial and optical resolution? (6) What novel roles will atoms play in technology? (7) What applications lie ahead for nitrogen-vacancy centres in diamond? (8) What is the future of quantum coherence, squeezing and entanglement for enhanced super-resolution and sensing? (9) How can we solve (some of) humanity's biggest problems through new quantum technologies? (10) What new understanding of materials and biological molecules will result from their dynamical characterization with free-electron lasers? (11) What new technologies and fundamental discoveries might quantum optics achieve by the end of this century? (12) What novel topological structures can be created and employed in quantum optics?
3.	Cotler, Jordan, et al. (författare) Entanglement Enabled Intensity Interferometry of different wavelengths of light 2021 Ingår i: Annals of Physics. - : Elsevier BV. - 0003-4916 .- 1096-035X. ; 424 Tidskriftsartikel (refereegranskat)abstract We propose methods to perform intensity interferometry of photons having two different wavelengths. Distinguishable particles typically cannot interfere with each other, but we overcome that obstacle by processing the particles via entanglement and projection so that they lead to the same final state at the detection apparatus. Specifically, we discuss how quasi-phase-matched nonlinear crystals can be used to convert a quantum superposition of light of different wavelengths onto a common wavelength, while preserving the phase information essential for their meaningful interference. We thereby gain access to a host of new observables, which can probe subtle frequency correlations and entanglement. Further, we generalize the van Cittert-Zernike formula for the intensity interferometry of extended sources, demonstrate how our proposal supports enhanced resolution of sources with different spectral character, and suggest potential applications.
4.	Cotler, Jordan, et al. (författare) Quantum Overlapping Tomography 2020 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 124:10 Tidskriftsartikel (refereegranskat)abstract It is now experimentally possible to entangle thousands of qubits, and efficiently measure each qubit in parallel in a distinct basis. To fully characterize an unknown entangled state of n qubits, one requires an exponential number of measurements in n, which is experimentally unfeasible even for modest system sizes. By leveraging (i) that single-qubit measurements can be made in parallel, and (ii) the theory of perfect hash families, we show that all k-qubit reduced density matrices of an n qubit state can be determined with at most e(O(k)) log(2) (n) rounds of parallel measurements. We provide concrete measurement protocols which realize this bound. As an example, we argue that with near-term experiments, every two-point correlator in a system of 1024 qubits could be measured and completely characterized in a few days. This corresponds to determining nearly 4.5 million correlators.
5.	Cotler, Jordan, et al. (författare) Superdensity operators for spacetime quantum mechanics 2018 Ingår i: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; :9 Tidskriftsartikel (refereegranskat)abstract We introduce superdensity operators as a tool for analyzing quantum information in spacetime. Superdensity operators encode spacetime correlation functions in an operator framework, and support a natural generalization of Hilbert space techniques and Dirac's transformation theory as traditionally applied to standard density operators. Superdensity operators can be measured experimentally, but accessing their full content requires novel procedures. We demonstrate these statements on several examples. The superdensity formalism suggests useful definitions of spacetime entropies and spacetime quantum channels. For example, we show that the von Neumann entropy of a superdensity operator is related to a quantum generalization of the Kolmogorov-Sinai entropy, and compute this for a many-body system. We also suggest experimental protocols for measuring spacetime entropies.
6.	Dai, Jin, et al. (författare) Truncated dynamics, ring molecules, and mechanical time crystals 2019 Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : AMER PHYSICAL SOC. - 2469-9926 .- 2469-9934. ; 99:2 Tidskriftsartikel (refereegranskat)abstract We identify circumstances where the effective descriptions of microscopic physical systems leads to a self-consistent reduced dynamics for a truncated subset of the original variables. The effective Hamiltonian involves unusual Poisson brackets that bring in noncommutative geometry. In idealized models of ring molecules, we find time crystal behavior is widespread.
7.	Elsik, Christine G., et al. (författare) The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution 2009 Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528 Tidskriftsartikel (refereegranskat)abstract To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
8.	Feng, Jia-Jin, et al. (författare) Quantum Computing by Coherent Cooling 2022 Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - 2469-9926 .- 2469-9934. ; 105:5 Tidskriftsartikel (refereegranskat)abstract Interesting problems in quantum computation take the form of finding low-energy states of (pseudo)spin systems with engineered Hamiltonians that encode the problem data. Motivated by the practical possibility of producing very low-temperature spin systems, we propose and exemplify the possibility to compute by coupling the computational spins to a quantum coherent bath that serves as a heat sink. The quantum tunneling effect provides additional cooling channels to accelerate the cooling process. We demonstrate both analytically and numerically that this strategy can achieve a quantum advantage in the unstructured search problem.
9.	Good, Michael R. R., et al. (författare) Finite thermal particle creation of Casimir light 2020 Ingår i: Modern Physics Letters A. - 0217-7323 .- 1793-6632. ; 35:3 Tidskriftsartikel (refereegranskat)abstract A new solution for an analytic spectrum of particle creation by an accelerating mirror (dynamical Casimir effect) is given. It is the first model to simultaneously radiate thermally and emit a finite number of particles.
10.	Good, Michael R. R., et al. (författare) Moving mirror model for quasithermal radiation fields 2020 Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 101:2 Tidskriftsartikel (refereegranskat)abstract We analyze the flow of energy and entropy emitted by a class of moving mirror trajectories which provide models for important aspects of the radiation fields produced by black hole evaporation. The mirror radiation fields provide natural, concrete examples of processes that follow thermal distributions for long periods, accompanied by transients which are brief and carry little net energy, yet ultimately represent pure quantum states. A burst of negative energy flux is a generic feature of these fields, but it need not be prominent.
11.	Greiter, Martin, et al. (författare) Adiabatic construction of hierarchical quantum Hall states 2021 Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 104:12 Tidskriftsartikel (refereegranskat)abstract We propose an exact model of anyon ground states including higher Landau levels, and use it to obtain fractionally quantized Hall states at filling fractions ν=p/(p(m−1)+1) with m odd, from integer Hall states at ν=p through adiabatic localization of magnetic flux. For appropriately chosen two-body potential interactions, the energy gap remains intact during the process, as we explicitly show for the p=2 series of states. The construction hence provides a major step towards establishing the existence of incompressible states at these fillings.
12.	Greiter, Martin, et al. (författare) Fractional Statistics 2024 Ingår i: Annual review of condensed matter physics. - 1947-5454. ; 15, s. 131-157 Forskningsöversikt (refereegranskat)abstract The quantum-mechanical description of assemblies of particles whose motion is confined to two (or one) spatial dimensions offers many possibilities that are distinct from bosons and fermions. We call such particles anyons. The simplest anyons are parameterized by an angular phase parameter theta. theta = 0,pi correspond to bosons and fermions, respectively; at intermediate values, we say that we have fractional statistics. In two dimensions, theta describes the phase acquired by the wave function as two anyons wind around one another counterclockwise. It generates a shift in the allowed values for the relative angular momentum. Composites of localized electric charge and magnetic flux associated with an abelian U(1) gauge group realize this behavior. More complex charge-flux constructions can involve nonabelian and product groups acting on a spectrum of allowed charges and fluxes, giving rise to nonabelian and mutual statistics. Interchanges of nonabelian anyons implement unitary transformations of the wave function within an emergent space of internal states. Anyons of all kinds are described by quantum field theories that include Chern-Simons terms. The crossings of one-dimensional anyons on a ring are unidirectional, such that a fractional phase theta acquired upon interchange gives rise to fractional shifts in the relative momenta between the anyons.The quasiparticle excitations of fractional quantum Hall states have long been predicted to include anyons. Recently, the anyon behavior predicted for quasiparticles in the v = 1/3 fractional quantum Hall state has been observed in both scattering and interferometric experiments. Excitations within designed systems, notably including superconducting circuits, can exhibit anyon behavior. Such systems are being developed for possible use in quantum information processing.
13.	Jiang, Qing-Dong, et al. (författare) Axial Casimir force 2019 Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 99:16 Tidskriftsartikel (refereegranskat)abstract Quantum fluctuations in vacuum can exert a dissipative force on moving objects, which is known as Casimir friction. Especially, a rotating particle in the vacuum will eventually slow down due to the dissipative Casimir friction. Here, we identify a dissipationless force by examining a rotating particle near a bi-isotropic media that generally breaks parity symmetry or/and time-reversal symmetry. The direction of the dissipationless vacuum force is always parallel with the rotating axis of the particle. We therefore call this dissipationless vacuum force the axial Casimir force.
14.	Jiang, Qing-Dong, et al. (författare) Chiral Casimir forces : Repulsive, enhanced, tunable 2019 Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 99:12 Tidskriftsartikel (refereegranskat)abstract Both theoretical interest and practical significance attach to the sign and strength of Casimir forces. A famous, discouraging no-go theorem states that the Casimir force between two bodies with reflection symmetry is always attractive. Here, we identify a promising way to avoid the assumptions of the no-go theorem, and propose a universal way to realize repulsive Casimir forces. We show that the sign and strength of Casimir forces can be adjusted by inserting optically active or gyrotropic media between bodies, and modulated by external fields.
15.	Jiang, Qing-Dong, et al. (författare) Geometric Induction in Chiral Superconductors 2020 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 124:19 Tidskriftsartikel (refereegranskat)abstract We consider a number of effects due to the interplay of superconductivity, electromagnetism, and elasticity, which are unique for thin membranes of layered chiral superconductors. Some of them should be within the reach of present technology, and could be useful for characterizing materials. More speculatively, the enriched control of Josephson junctions they afford might find useful applications.
16.	Jiang, Qing-Dong, et al. (författare) Quantum atmospherics for materials diagnosis 2019 Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 99:20 Tidskriftsartikel (refereegranskat)abstract Symmetry-breaking states of matter can transmit symmetry breaking to nearby atoms or molecular complexes, perturbing their spectra. We calculate one such effect, involving the axion electrodynamics relevant to topological insulators, quantitatively, and identify a signature for T violating superconductivity. We provide an operator framework whereby effects of this kind can be analyzed systematically.
17.	Kedem, Yaron, et al. (författare) Black and white holes at material junctions 2020 Ingår i: Physical Review Research. - 2643-1564. ; 2:4 Tidskriftsartikel (refereegranskat)abstract Electrons in type II Weyl semimetals display one-way propagation, which supports totally reflecting behavior at an endpoint, as one has for black hole horizons viewed from the inside. Junctions of type I and type II lead to equations identical to what one has near black hole horizons, but the physical implications, we suggest, are quite different from expectations which are conventional in that context. The time-reversed, “white hole” configuration is also physically accessible.
18.	Lawson, Matthew, et al. (författare) Tunable Axion Plasma Haloscopes 2019 Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 123:14 Tidskriftsartikel (refereegranskat)abstract We propose a new strategy for searching for dark matter axions using tunable cryogenic plasmas. Unlike current experiments, which repair the mismatch between axion and photon masses by breaking translational invariance (cavity and dielectric haloscopes), a plasma haloscope enables resonant conversion by matching the axion mass to a plasma frequency. A key advantage is that the plasma frequency is unrelated to the physical size of the device, allowing large conversion volumes. We identify wire metamaterials as a promising candidate plasma, wherein the plasma frequency can be tuned by varying the interwire spacing. For realistic experimental sizes, we estimate competitive sensitivity for axion masses of 35-400 mu eV, at least.
19.	Liu, Lu-Chuan, et al. (författare) Improved Spatial Resolution Achieved by Chromatic Intensity Interferometry 2021 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 127:10 Tidskriftsartikel (refereegranskat)abstract Interferometers are widely used in imaging technologies to achieve enhanced spatial resolution, but require that the incoming photons be indistinguishable. In previous work, we built and analyzed color erasure detectors, which expand the scope of intensity interferometry to accommodate sources of different colors. Here we demonstrate experimentally how color erasure detectors can achieve improved spatial resolution in an imaging task, well beyond the diffraction limit. Utilizing two 10.9-mm- aperture telescopes and a 0.8 m baseline, we measure the distance between a 1063.6 and a 1064.4 nm source separated by 4.2 mm at a distance of 1.43 km, which surpasses the diffraction limit of a single telescope by about 40 times. Moreover, chromatic intensity interferometry allows us to recover the phase of the Fourier transform of the imaged objects-a quantity that is, in the presence of modest noise, inaccessible to conventional intensity interferometry.
20.	Millar, Alexander J., et al. (författare) Searching for dark matter with plasma haloscopes 2023 Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 107:5 Tidskriftsartikel (refereegranskat)abstract We summarize the recent progress of the Axion Longitudinal Plasma Haloscope (ALPHA) Consortium, a new experimental collaboration to build a plasma haloscope to search for axions and dark photons. The plasma haloscope is a novel method for the detection of the resonant conversion of light dark matter to photons. ALPHA will be sensitive to QCD axions over almost a decade of parameter space, potentially discovering dark matter and resolving the strong CP problem. Unlike traditional cavity haloscopes, which are generally limited in volume by the Compton wavelength of the dark matter, plasma haloscopes use a wire metamaterial to create a tuneable artificial plasma frequency, decoupling the wavelength of light from the Compton wavelength and allowing for much stronger signals. We develop the theoretical foundations of plasma haloscopes and discuss recent experimental progress. Finally, we outline a baseline design for ALPHA and show that a full-scale experiment could discover QCD axions over almost a decade of parameter space.
21.	Morampudi, Siddhardh C., et al. (författare) Spectroscopy of Spinons in Coulomb Quantum Spin Liquids 2020 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 124:9 Tidskriftsartikel (refereegranskat)abstract We calculate the effect of the emergent photon on threshold production of spinons in U(1) Coulomb spin liquids such as quantum spin ice. The emergent Coulomb interaction modifies the threshold production cross-section dramatically, changing the weak turn-on expected from the density of states to an abrupt onset reflecting the basic coupling parameters. The slow photon typical in existing lattice models and materials suppresses the intensity at finite momentum and allows profuse Cerenkov radiation beyond a critical momentum. These features are broadly consistent with recent numerical and experimental results.
22.	Müller, Eike Christoph (författare) Axionlike particles, quantum loops, and supernovae : The role of quantum loop corrections for astrophysical ALPs 2022 Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract In this thesis the quantum field theory and astrophysical phenomenology of axionlike particles (ALPs) are studied. The effective field theory of ALPs is reviewed with a special focus on quantum loops, the renormalization group equations, and the equivalent forms of the interaction between ALPs and fermions.To study the phenomenology of ALPs, both as dark matter candidate in the first paper that this thesis is based on, and as they are produced in supernova explosions in the second paper, an effective coupling between ALPs and photons is defined. In this way, the full one-loop effect of ALP-electron interactions can straightforwardly be incorporated in phenomenological analyses.It is pointed out that the effective coupling is different in decay and ALP-photon conversion processes. Importantly, the resulting loop-induced ALP-photon conversion rate does not vanish for ALPs much lighter than the electron, as was often stated in the literature.With this field theoretical basis, it is pointed out in the first paper that the decay of ALPs into photons via quantum loops has severe consequences for direct detection searches of ALP dark matter. In a large part of the parameter space that these experiments are sensitive to, the ALP would either not be long-lived enough to be dark matter, or the x-rays or gamma-rays originating from the decays of the ALP relic density should have been observed by indirect detection searches. Hence, while more heavy and strongly interacting ALPs coupled to electrons cannot be dark matter, many relatively lighter and weaker interacting models are ruled out already by indirect detection constraints.Furthermore, ALPs can be produced efficiently in supernovae even if they interact only very weakly. The absence of anomalous cooling in SN1987A constrains the ALP-photon and ALP-electron interactions. Similarly, since no gamma-rays arrived on earth directly after the observation of the neutrino burst of SN1987A, further constraints can be derived.Using the effective loop-induced coupling, some of the strongest bounds on the coupling between electrons and ALPs in the keV and MeV mass range are calculated in the second paper. Additionally, some technical details of the calculation are discussed and improved.
23.	Niemi, Antti, et al. (författare) Nobel Symposium 148 : Graphene and quantum matter 2012 Ingår i: Physica scripta. T. - 0281-1847. ; :T146 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract The 2010 Nobel Symposium on Graphene and Quantum Matter, was held at the Grand Hotel in Saltsjöbaden south of Stockholm on 27-31 May. The main theme of the meeting was graphene, and the symposium turned out to be very timely: two of the participants, Andre Geim and Kanstantin Novoselov returned to Stockholm less then six months later to receive the 2010 Nobel Prize in Physics. In these proceedings leading experts give up-to-date, historical, experimental, theoretical and technological perspectives on the remarkable material graphene, and several papers also make connections to other states of quantum matter. Saltsjöbaden is beautifully situated in the inner archipelago of Stockholm. It provided a pleasant setting for the talks and the ensuing discussions that took place in an enthusiastic and friendly atmosphere. The social programme included a boat trip in the light summer night and a dinner at the renowned Grand Hotel. These proceedings are ordered thematically, starting with historical overviews, followed by first experimental and then theoretical papers on the physics of graphene. Next are several papers addressing more general topics in quantum matter and finally contributions on the technological applications of graphene. We hope that this volume will serve as a source of knowledge and inspiration for any physicist interested in graphene, and at the same time provide a snapshot of a young field of research that is developing at very high speed. We are grateful to Marja Fahlander for excellent administrative support, and to the Nobel Foundation who funded the symposium.
24.	Parikh, Maulik, et al. (författare) Quantum Mechanics of Gravitational Waves 2021 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 127:8 Tidskriftsartikel (refereegranskat)abstract For the purpose of analyzing observed phenomena, it has been convenient, and thus far sufficient, to regard gravity as subject to the deterministic principles of classical physics, with the gravitational field obeying Newton’s law or Einstein’s equations. Here we treat the gravitational field as a quantum field and determine the implications of such treatment for experimental observables. We find that falling bodies in gravity are subject to random fluctuations (“noise”) whose characteristics depend on the quantum state of the gravitational field. We derive a stochastic equation for the separation of two falling particles. Detection of this fundamental noise, which may be measurable at gravitational wave detectors, would vindicate the quantization of gravity, and reveal important properties of its sources.
25.	Parikh, Maulik, et al. (författare) Signatures of the quantization of gravity at gravitational wave detectors 2021 Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 104:4 Tidskriftsartikel (refereegranskat)abstract We develop a formalism to calculate the response of a model gravitational wave detector to a quantized gravitational field. Coupling a detector to a quantum field induces stochastic fluctuations (“noise”) in the length of the detector arm. The statistical properties of this noise depend on the choice of quantum state of the gravitational field. We characterize the noise for vacuum, coherent, thermal, and squeezed states. For coherent states, corresponding to classical gravitational configurations, we find that the effect of gravitational field quantization is small. However, the standard deviation in the arm length can be enhanced—possibly significantly—when the gravitational field is in a noncoherent state. The detection of this fundamental noise could provide direct evidence for the quantization of gravity and for the existence of gravitons.
26.	Parikh, Maulik, et al. (författare) The noise of gravitons 2020 Ingår i: International Journal of Modern Physics D. - 0218-2718. ; 29:14 Tidskriftsartikel (refereegranskat)abstract We show that when the gravitational field is treated quantum-mechanically, it induces fluctuations - noise - in the lengths of the arms of gravitational wave detectors. The characteristics of the noise depend on the quantum state of the gravitational field and can be calculated exactly in several interesting cases. For coherent states, the noise is very small, but it can be greatly enhanced in thermal and (especially) squeezed states. Detection of this fundamental noise would constitute direct evidence for the quantization of gravity and the existence of gravitons.
27.	Qu, Luo-Yuan, et al. (författare) Chromatic interferometry with small frequency differences 2020 Ingår i: Optics Express. - 1094-4087. ; 28:22, s. 32294-32301 Tidskriftsartikel (refereegranskat)abstract By developing a 'two-crystal' method for color erasure, we can broaden the scope of chromatic interferometry to include optical photons whose frequency difference falls outside of the 400 nm to 4500 nm wavelength range, which is the passband of a PPLN crystal. We demonstrate this possibility experimentally, by observing interference patterns between sources at 1064.4 nm and 1063.6 nm, corresponding to a frequency difference of about 200 GHz.
28.	Qu, Luo-Yuan, et al. (författare) Color Erasure Detectors Enable Chromatic Interferometry 2019 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 123:24 Tidskriftsartikel (refereegranskat)abstract By engineering and manipulating quantum entanglement between incoming photons and experimental apparatus, we construct single-photon detectors which cannot distinguish between photons of very different wavelengths. These color-erasure detectors enable a new kind of intensity interferometry, with potential applications in microscopy and astronomy. We demonstrate chromatic interferometry experimentally, observing robust interference using both coherent and incoherent photon sources.
29.	Ravensburg, Eike Christoph, 1995- (författare) Astrophysical probes of axionlike particles 2023 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract This thesis is a contribution to the search for new fundamental physics in the form of axionlike particles (ALPs). ALPs are relatively light and feebly interacting particles that are part of many theories extending the Standard Model of particle physics, e.g., to solve the strong-CP problem, the dark matter problem, or quantum gravity in the form of string theory. We use astrophysical observations mainly related to core-collapse supernovae to search for signatures of the existence of ALPs.In the first part of this thesis, we study in some detail the effective field theory of ALPs with a focus on quantum loop effects. These loops necessarily induce correlations between the effective couplings of the theory such that, e.g., the interaction between ALPs and photons sourced by quantum loops due to their coupling to leptons cannot be neglected. In the second part of the thesis, as well as in three of the publications that it is comprised of, we demonstrate the importance of the effective ALP-photon coupling defined here for dark matter ALPs, whose loop induced decay to photons excludes a large region of their parameter space that was believed to be accessible to direct detection experiments, as well as ALPs produced in supernova explosions. Through the loop-induced interaction with photons more ALPs can be produced in supernovae than was calculated previously. Additionally, the photon-decay channel implies ways in which ALPs could have been observed that would not be possible if they only interacted with leptons. For instance, if a nearby supernova such as SN 1987A or the recently observed SN 2023ixf, emitted a large number of ALPs that afterwards decayed into gamma-ray photons, such a signal could have been detected by telescopes. The precise prediction of this signal is a further focus of this thesis and three of the included publications. Additionally, we improve many technical aspects of the determination of the number and energy of ALPs produced in supernovae, as well as their reabsorption before they can leave the hot and dense inner regions. This enables us to derive some of the strongest, and most reliable bounds to date on the parameters of ALPs.
30.	Reig, Mario, et al. (författare) A model of comprehensive unification 2017 Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 774, s. 667-670 Tidskriftsartikel (refereegranskat)abstract Comprehensive - that is, gauge and family - unification using spinors has many attractive features, but it has been challenged to explain chirality. Here, by combining an orbifold construction with more traditional ideas, we address that difficulty. Our candidate model features three chiral families and leads to an acceptable result for quantitative unification of couplings. A potential target for accelerator and astronomical searches emerges.
31.	Reig, Mario, et al. (författare) SO(3) family symmetry and axions 2018 Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 98:9 Tidskriftsartikel (refereegranskat)abstract Motivated by the idea of comprehensive unification, we study a gauged SO(3) flavor extension of the extended Standard Model, including right-handed neutrinos and a Peccei-Quinn symmetry with simple charge assignments. The model accommodates the observed fermion masses and mixings and yields a characteristic, successful relation among them. The Peccei-Quinn symmetry is an essential ingredient.
32.	Shapere, Alfred D., et al. (författare) Regularizations of time-crystal dynamics 2019 Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 116:38, s. 18772-18776 Tidskriftsartikel (refereegranskat)abstract We demonstrate that nonconvex Lagrangians, as contemplated in the theory of time crystals, can arise in the effective description of conventional, physically realizable systems. Such embeddings resolve dynamical singularities which arise in the reduced description. Microstructure featuring intervals of fixed velocity interrupted by quick resets-Sisyphus dynamics-is a generic consequence. In quantum mechanics, this microstructure can be blurred, leaving entirely regular behavior.
33.	Shaposhnikov, Leon, et al. (författare) Emergent axion response in multilayered metamaterials 2023 Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 108:11 Tidskriftsartikel (refereegranskat)abstract We consider the design of metamaterials whose behavior embodies the equations of axion electrodynamics. We derive an effective medium description of an assembly of magneto-optical layers with out-of-plane magnetization analytically and show how to achieve effective axion response with tunable parameters. We display some key predictions and validate them numerically.
34.	Stålhammar, Marcus, 1994-, et al. (författare) Emergent Chern-Simons interactions in 3+1 dimensions 2024 Ingår i: Physical Review B. - : American Physical Society (APS). - 2469-9950 .- 2469-9969. ; 109:6 Tidskriftsartikel (refereegranskat)abstract Parity-violating superconductors can support a low-dimension local interaction that becomes, upon condensation, a purely spatial Chern-Simons term. Solutions to the resulting generalized London equations can be obtained from solutions of the ordinary London equations with a complex penetration depth, and suggest several remarkable physical phenomena. The problem of flux exclusion by a sphere brings in an anapole moment, the problem of current-carrying wires brings in an azimuthal magnetic field, and the problem of vortices brings in currents along the vortices. We demonstrate that interactions of this kind, together with a conceptually related dimensionally reduced Chern-Simons interaction, can arise from physically plausible microscopic interactions.
35.	Visinelli, Luca, et al. (författare) Dilute and dense axion stars 2018 Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 777, s. 64-72 Tidskriftsartikel (refereegranskat)abstract Axion stars are hypothetical objects formed of axions, obtained as localized and coherently oscillating solutions to their classical equation of motion. Depending on the value of the field amplitude at the core vertical bar theta(0)vertical bar vertical bar theta(r = 0)vertical bar, the equilibrium of the system arises from the balance of the kinetic pressure and either self-gravity or axion self-interactions. Starting from a general relativistic framework, we obtain the set of equations describing the configuration of the axion star, which we solve as a function of vertical bar theta(0)vertical bar. For small vertical bar theta(0)vertical bar less than or similar to 1, we reproduce results previously obtained in the literature, and we provide arguments for the stability of such configurations in terms of first principles. We compare qualitative analytical results with a numerical calculation. For large amplitudes vertical bar theta(0)vertical bar greater than or similar to 1, the axion field probes the full non-harmonic QCD chiral potential and the axion star enters the densebranch. Our numerical solutions show that in this latter regime the axions are relativistic, and that one should not use a single frequency approximation, as previously applied in the literature. We employ a multi-harmonic expansion to solve the relativistic equation for the axion field in the star, and demonstrate that higher modes cannot be neglected in the dense regime. We interpret the solutions in the dense regime as pseudo-breathers, and show that the life-time of such configurations is much smaller than any cosmological time scale.
36.	Wilczek, Frank, 1951- (författare) Ambiguity, invisibility, and negativity 2024 Ingår i: Journal of Physics A. - 1751-8113 .- 1751-8121. ; 57:18 Tidskriftsartikel (refereegranskat)abstract Many widely different problems have a common mathematical structure wherein limited knowledge leads to ambiguity that can be captured conveniently using a concept of invisibility that requires the introduction of negative values for quantities that are inherently positive. Here I analyze three examples taken from perception theory, rigid body mechanics, and quantum measurement.
37.	Wilczek, Frank, et al. (författare) Resonant Quantum Search with Monitor Qubits 2020 Ingår i: Chinese Physics Letters. - 0256-307X .- 1741-3540. ; 37:5 Tidskriftsartikel (refereegranskat)abstract We present an algorithm for the generalized search problem (searching k marked items among N items) based on a continuous Hamiltonian and exploiting resonance. This resonant algorithm has the same time complexity O(N/k)
38.	Wu, Biao, et al. (författare) Quantum independent-set problem and non-Abelian adiabatic mixing 2020 Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - 2469-9926 .- 2469-9934. ; 101:1 Tidskriftsartikel (refereegranskat)abstract We present an efficient quantum algorithm for independent-set problems in graph theory, based on non-Abelian adiabatic mixing. We illustrate the performance of our algorithm with analysis and numerical calculations for two different types of graphs, with the number of edges proportional to the number of vertices or its square. Our quantum algorithm is compared to the corresponding quantum circuit algorithms and classical algorithms. Non-Abelian adiabatic mixing can be a general technique to aid exploration in a landscape of near-degenerate ground states.
39.	Yang, Kang, et al. (författare) Exceptional dynamics of interacting spin liquids 2022 Ingår i: Physical Review Research. - 2643-1564. ; 4:4 Tidskriftsartikel (refereegranskat)abstract We show that interactions in quantum spin liquids can result in non-Hermitian phenomenology that differs qualitatively from mean-field expectations. We demonstrate this in two prominent cases through the effects of phonons and disorder on a Kitaev honeycomb model. Using analytic and numerical calculations, we show the generic appearance of exceptional points and rings depending on the symmetry of the system. Their existence is reflected in dynamical observables including the dynamic structure function measured in neutron scattering. The results point to different phenomenological features in realizable spin liquids that must be incorporated into the analysis of experimental data and also indicate that spin liquids could be generically stable to wider classes of perturbations.
40.	Yin, Xu-Fei, et al. (författare) Solving independent set problems with photonic quantum circuits 2023 Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - 0027-8424 .- 1091-6490. ; 120:22 Tidskriftsartikel (refereegranskat)abstract An independent set (IS) is a set of vertices in a graph such that no edge connects any two vertices. In adiabatic quantum computation [E. Farhi, et al., Science 292, 472–475 (2001); A. Das, B. K. Chakrabarti, Rev. Mod. Phys. 80, 1061–1081 (2008)], a given graph G(V, E) can be naturally mapped onto a many-body Hamiltonian , with edges ? being the two-body interactions between adjacent vertices ?. Thus, solving the IS problem is equivalent to finding all the computational basis ground states of . Very recently, non-Abelian adiabatic mixing (NAAM) has been proposed to address this task, exploiting an emergent non-Abelian gauge symmetry of [B. Wu, H. Yu, F. Wilczek, Phys. Rev. A 101, 012318 (2020)]. Here, we solve a representative IS problem ?(8,7) by simulating the NAAM digitally using a linear optical quantum network, consisting of three C-Phase gates, four deterministic two-qubit gate arrays (DGA), and ten single rotation gates. The maximum IS has been successfully identified with sufficient Trotterization steps and a carefully chosen evolution path. Remarkably, we find IS with a total probability of 0.875(16), among which the nontrivial ones have a considerable weight of about 31.4%. Our experiment demonstrates the potential advantage of NAAM for solving IS-equivalent problems.
41.	Yu, Hongye, et al. (författare) Quantum Algorithm for Approximating Maximum Independent Sets 2021 Ingår i: Chinese Physics Letters. - 0256-307X .- 1741-3540. ; 38:3 Tidskriftsartikel (refereegranskat)abstract We present a quantum algorithm for approximating maximum independent sets of a graph based on quantum non-Abelian adiabatic mixing in the sub-Hilbert space of degenerate ground states, which generates quantum annealing in a secondary Hamiltonian. For both sparse and dense random graphs G, numerical simulation suggests that our algorithm on average finds an independent set of size close to the maximum size α(G) in low polynomial time. The best classical algorithms, by contrast, produce independent sets of size about half of α(G) in polynomial time.
42.	Zaletel, Michael P., et al. (författare) Colloquium : Quantum and classical discrete time crystals 2023 Ingår i: Reviews of Modern Physics. - 0034-6861 .- 1539-0756. ; 95:3 Forskningsöversikt (refereegranskat)abstract The spontaneous breaking of time-translation symmetry has led to the discovery of a new phase of matter: the discrete time crystal. Discrete time crystals exhibit rigid subharmonic oscillations that result from a combination of many-body interactions, collective synchronization, and ergodicity breaking. This Colloquium reviews recent theoretical and experimental advances in the study of quantum and classical discrete time crystals. The breaking of ergodicity is focused upon as the key to discrete time crystals and the delaying of ergodicity as the source of numerous phenomena that share many of the properties of discrete time crystals, including the ac Josephson effect, coupled map lattices, and Faraday waves. Theoretically, there is a diverse array of strategies to stabilize time crystalline order in both closed and open systems, ranging from localization and prethermalization to dissipation and error correction. Experimentally, many-body quantum simulators provide a natural platform for investigating signatures of time-crystalline order; recent work utilizing trapped ions, solid-state spin systems, and superconducting qubits are reviewed. Finally, this Colloquium concludes by describing outstanding challenges in the field and a vision for new directions on both the experimental and theoretical fronts.

Skapa referenser, mejla, bekava och länka

Länka till träfflistan

Träfflista för sökning "WFRF:(Wilczek Frank) "

Avgränsa träffmängd

År