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![X-ray image of Coma galaxy cluster, from Ref. [40].](publication/334022244/figure/fig5/AS:773888724189185@1561520858096/X-ray-image-of-Coma-galaxy-cluster-from-Ref-40.jpg)
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![Figure 17. X-ray image of Coma galaxy cluster, from Ref. [40].](publication/334022244/figure/fig5/AS:773888724189185@1561520858096/X-ray-image-of-Coma-galaxy-cluster-from-Ref-40_Q320.jpg)
The new field of multi-messenger astronomy aims at the study of astronomical sources using different types of “messenger” particles: photons, neutrinos, cosmic rays and gravitational waves. These lectures provide an introductory overview of the observational techniques used for each type of astronomical messenger, of different types of astronomical...
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The measurement of minuscule forces and displacements with ever greater precision is inhibited by the Heisenberg uncertainty principle, which imposes a limit to the precision with which the position of an object can be measured continuously, known as the standard quantum limit1–4. When light is used as the probe, the standard quantum limit arises f...
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... Recent astronomical observations of an unusual gamma-ray burst and the discovery of gravitational waves originating from a binary neutron-star merger have significantly advanced the study of dense matter physics (Abbott et al., 2017). In fact, these observations marked the beginning of the multi-messenger era, which combines various techniques such as neutrino detection, X-ray telescopes, radio astronomy, etc (Neronov, 2019). ...
Isoscalar giant resonances are nuclear collective excitations associated with the oscillation in phase of protons and neutrons according to a certain multipolarity $L$. In particular, the isoscalar giant monopole resonance ($L=0$) is the strongest nuclear compression mode, and its excitation energy is directly related to the compression modulus for finite nuclei. Typically, microscopic calculations are utilized to establish a relationship between the experimental compression modulus and the nuclear incompressibility that is a crucial parameter of the equation of state for nuclear matter. The incompressibility of nuclear matter has been determined with an accuracy of 10 to 20\% using relativistic and non-relativistic microscopic models for describing the monopole distributions in ${}^{208}$Pb and ${}^{90}$Zr isotopes. However, the same theoretical models are not able to describe data for open-shell nuclei, such as those of tin and cadmium isotopes. In fact, only effective interactions with a softer nuclear-matter incompressibility are able to predict the centroid energy of monopole distributions for open-shell nuclei. An unified description of the monopole resonance in ${}^{208}$Pb and other open-shell nuclei remains unsolved from the theory side. Most of this uncertainty is due to our poor knowledge of the symmetry energy, which is another essential component of the equation of state of nuclear matter. Therefore, new experimental data along isotopic chains covering a wide range in $N/Z$ ratios, including neutron-deficient and neutron-rich nuclei, are of paramount importance for determining both the nuclear-matter incompressibility and the symmetry energy more precisely.
... Multi-messenger astrophysics [10,11] combines observations from many modalities (e.g., gravity waves, neutrinos, EM spectra) to study physical phenomena in the cosmos. Because some events of interest, such as binary neutron star mergers, occur on a time Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. ...
... Multi-messenger astrophysics seeks to learn about gravitational collapse of end-of-life massive stars, neutron stars and neutrino emission, supernova and supernova remnants, pulsars and pulsar wind nebulae, stellar mass black holes, and other physical phenomena [4]. The core idea is that different observational modalities teach us different things about each of these phenomena. ...
... The range of observational modalities is quite large, including optical telescopes, radio telescopes, X-ray telescopes, γray telescopes, neutrino telescopes, and gravity wave detectors [4]. While some of these instruments have a wide FoV (e.g., the gravity wave detectors), many do not. ...
... Moreover, there are many different particle types (electrons, holes, excitons, electron and nuclear spins, phonons, and photons) that need to be modeled and understood in order for semiconductor-based qubits to reach their full potential. Borrowing terminology that originated in the astrophysics community [136] and has recently been discussed in terms of computational many-body physics [137], the terms "multimethod and multimessenger studies" encapsulate the need for diverse methods capable of accurately modeling multiple different particle types, often at the same time and different levels of theory. To this end, we postulate that there will be no single method nor computational formalism that would be able to be universally applied to modeling semiconductor-based qubit systems, but we are confident that intelligently combining and extending current methods will allow for accurate modeling of the inherently large system sizes of semiconductor-based multiqubit systems. ...
The field of materials for quantum information science is rapidly growing with a focus on scaling and integrating new solid-state qubits. However, despite the extraordinary progress, major challenges must still be overcome for scaling. Specifically, there is a critical need for efficient coupling of tens to hundreds of solid-state qubits and multiqubit error correction to mitigate environmental interactions. This Perspective looks forward to the challenges ahead in the realization of multiqubit operations and collective phenomena with a focus on solid-state quantum materials. We provide a theorists’ point of view on the modeling and rational design of these multiqubit systems. Our Perspective identifies a path for bridging the gap between the model Hamiltonians used to develop quantum algorithms and control sequences and the ab initio calculations used to understand and characterize single solid-state-based qubits.
... . The non-thermal sources observed by radio telescopes include sources in the Milky Way galaxy, such as pulsars, pulsar wind nebulae and supernova remnants. Among extragalactic sources, the dominant class is radio galaxies which are radioloud AGN, powered by the activity of a Super-Massive Black Hole (SMBH) in the center of each galaxy [36] [36] Neronov, 'Introduction to multi-messenger astronomy' ...
... IR and Optical-UV astronomy higher frequencies, photons are predominantly produced by objects heated up to the temperature at which the typical energy of black body photons (E bb = 3k B T ≃ 3[T/10 4 K] eV) falls into the respective band. Most of the IR/visible/UV light we detect is thermal emission, i.e. the one produced by stars, the interior of core collapse supernova or the merger of neutron stars [36] [36] Neronov, 'Introduction to multi-messenger astronomy' ...
... . At X-ray astronomy wavelengths of the order of the size of atoms (λ = E −1 γ ≃ 10 −7 [E γ /1 keV] cm) we find X-ray photons [36]. Their energy is about 3 orders of magnitude higher than that of the visible light photons, and their flux is by three orders of magnitude lower. ...
Das IceCube Neutrino Teleskop hat einen diffusen Fluss hochenergetischen astrophysikalischen Neutrinos entdeckten. Allerdings sind die Quellen die für die Mehrzahl der nachgewiesenen Neutrinos verantwortlich sind, noch unbekannt. Diese Arbeit untersucht die Möglichkeit, dass der beobachtete Neutrino-Fluss im Zentrum von aktiven galaktischen Kernen (AGN) erzeugt wird. Eine Stacking-Analyse wird durchgeführt, um die Korrelation zwischen verschiedenen Subpopulationen von AGN und hochenergetischen Neutrinos unter Verwendung von IceCube-Daten aus acht Jahren zu testen. AGN werden anhand ihrer Radioemission, Infrarot-Farbeigenschaften und ihres Röntgenflusses. Die Leuchtkraft der Akkretionsscheibe wird verwendet, um den Beitrag ausgewählter Galaxien zum Neutrinosignal zu gewichten. Die leuchtende AGN-Population trägt zu ~52% des von IceCube gemessenen diffusen Flusses bei 100 TeV mit einem Best-Fit-Spektralindex von 2 bei mit 2.83 sigma post-trial Signifikanz. Für die AGN-Probe mit geringer Leuchtkraft wird eine Signifikanz nach dem Versuch von nur 0.66 sigma gefunden, daher werden Obergrenzen festgelegt. Unter Annahme des Spektralindex für den astrophysikalischen Fluss von 2 und einer gleichverteilten gleiche Zusammensetzung Neutrinoflavour-Zusammensetzung auf der Erde, wird eine obere Flussgrenze berechnet, die den maximalen Beitrag der Kerne von AGN mit geringer Leuchtkraft zum diffusen TeV-PeV-Neutrino-Fluss auf ~51% bei 100 TeV beschränkt. Für diese Arbeit wurde auch eine neue Rekonstruktionsmethode entwickelt. In IceCube werden hochenergetische Myon-neutrinos durch die sekundären Myonen identifiziert, die durch Wechselwirkungen über geladene Ströme mit dem Eis erzeugt werden. In dem hier vorgestellten Rekonstruktionsschema wird die erwartete Ankunftszeitverteilung durch ein vorbestimmtes stochastisches Myon-Energieverlustprofil parametrisiert. Diese realistischere Parametrisierung führt zu einer Verbesserung der Myon-Winkelauflösung in IceCube um etwa 20%.
... Our study also interrogates the model through a set of different physical observables, spanning thermodynamic properties and single-particle correlation functions (the Green function and associated self-energy) as well as two-particle correlations (the spin correlation function and correlation length). Because of this wide spectrum of both methods and observables, we borrow terminology from the astrophysics community in designating our work as a "multimethod, multimessenger study" [19]. ...
The Hubbard model represents the fundamental model for interacting quantum systems and electronic correlations. Using the two-dimensional half-filled Hubbard model at weak coupling as a testing ground, we perform a comparative study of a comprehensive set of state-of-the-art quantum many-body methods. Upon cooling into its insulating antiferromagnetic ground state, the model hosts a rich sequence of distinct physical regimes with crossovers between a high-temperature incoherent regime, an intermediate-temperature metallic regime, and a low-temperature insulating regime with a pseudogap created by antiferromagnetic fluctuations. We assess the ability of each method to properly address these physical regimes and crossovers through the computation of several observables probing both quasiparticle properties and magnetic correlations, with two numerically exact methods (diagrammatic and determinantal quantum Monte Carlo methods) serving as a benchmark. By combining computational results and analytical insights, we elucidate the nature and role of spin fluctuations in each of these regimes. Based on this analysis, we explain how quasiparticles can coexist with increasingly long-range antiferromagnetic correlations and why dynamical mean-field theory is found to provide a remarkably accurate approximation of local quantities in the metallic regime. We also critically discuss whether imaginary-time methods are able to capture the non-Fermi-liquid singularities of this fully nested system.
... Our study also interrogates the model through a set of different physical observables, spanning thermodynamic properties, single-particle correlation functions (the Green function and associated self-energy) as well as two-particle correlations (the spin correlation function and correlation length). Because of this wide spectrum of both methods and observables, we have borrowed terminology from the astrophysics community in designating our work as a 'multi-method, multi messenger study' [19]. ...
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The Hubbard model represents the fundamental model for interacting quantum systems and electronic correlations. Using the two-dimensional half-filled Hubbard model at weak coupling as testing grounds, we perform a comparative study of a comprehensive set of state of the art quantum many-body methods. Upon cooling into its insulating antiferromagnetic ground-state, the model hosts a rich sequence of distinct physical regimes with crossovers between a high-temperature incoherent regime, an intermediate temperature metallic regime and a low-temperature insulating regime with a pseudogap created by antiferromagnetic fluctuations. We assess the ability of each method to properly address these physical regimes and crossovers through the computation of several observables probing both quasiparticle properties and magnetic correlations, with two numerically exact methods (diagrammatic and determinantal quantum Monte Carlo) serving as a benchmark. By combining computational results and analytical insights, we elucidate the nature and role of spin fluctuations in each of these regimes and explain, in particular, how quasiparticles can coexist with increasingly long-range antiferromagnetic correlations in the metallic regime. We also critically discuss whether imaginary time methods are able to capture the non-Fermi liquid singularities of this fully nested system.
... The energy range accessible by photons, however, spans much further than the optical, going from low-energy radio observations of less than meV to ∼ 100 TeV γ-rays, some 15 orders of magnitude in energy. Today the broad-band spectral energy distribution of electromagnetic radiation is measured by a multitude of different instruments, using different techniques both ground-based and in space (for a review see [1]). The fact that Nature provides us with such a wide spread of different wavelengths is owed to the abundance of mechanisms that cause electromagnetic radiation, going beyond the thermal processes mentioned before. ...
... The latest GRB190829A ranges in between the two with a time delay of four hours and a detection well above 5σ , but is unusual with respect to its closeness of z = 0.0785. These events span the parameter space of TeV GRB observations with good chances for detection (1) in fast follow-up observations, (2) for very bright objects, and (3) for very close objects. Probing GRBs as extreme accelerators at TeV energies has become reality, even at afterglow time scales of days! ...
Multi-messenger astronomy has experienced an explosive development in the past few years. While not being a particularly young field, it has recently attracted a lot of attention by several major discoveries and unprecedented observation campaigns covering the entity of the electromagnetic spectrum as well as observations of cosmic rays, neutrinos, and gravitational waves. The exploration of synergies is in full steam and requires close cooperation between different instruments. Here I give an overview over the subject of multi-messenger astronomy and its virtues compared to classical "single messenger" observations, present the recent break throughs of the field, and discuss some of its organisational and technical challenges.
... In recent years the LIGO-VIRGO collaboration has reported the direct detection of gravitational waves from merging black holes [1][2][3][4][5], and neutron stars [6]. These detections have also been studied in the electromagnetic spectrum [7][8][9][10], representing new examples of multi-messenger astronomy [11]. Moreover, the current O3 run of the LIGO-VIRGO collaboration is already reporting a large amount of new events [12]. ...
We calculate the quasinormal modes of static spherically symmetric dilatonic Reissner-Nordstr\"om black holes for general values of the electric charge and of the dilaton coupling constant. The spectrum of quasinormal modes is composed of five families of modes: polar and axial gravitational-led modes, polar and axial electromagnetic-led modes, and polar scalar-led modes. We make a quantitative analysis of the spectrum, revealing its dependence on the electric charge and on the dilaton coupling constant. For large electric charge and large dilaton coupling, strong deviations from the Reissner-Nordstr\"om modes arise. In particular, isospectrality is strongly broken, both for the electromagnetic-led and the gravitational-led modes, for large values of the charge.
Context. Observations of the effect of microlensing in gravitationally lensed quasars can be used to study the structure of active galactic nuclei on distance scales down to the sizes of a supermassive black hole’s powering source activity.
Aims. We searched for a microlensing effect in the signal from a gravitationally lensed blazar, B0218+357, in a very-high-energy γ -ray band.
Methods. We combined observations of a bright flare of the source in 2014 by the Fermi Large Area Telescope and MAGIC telescopes in the 0.1 − 300 GeV and 65 − 175 GeV energy ranges, respectively. Using the time-delayed leading and trailing signals from two gravitationally lensed images of the source, we measured the magnification factor at the moment of the flare. We used the scaling of the maximal magnification factor with the source size to constrain the size of the γ -ray emission region in the wide 0.1 − 175 GeV energy range.
Results. The magnification factor in the very-high-energy band that we derived from our comparison of Fermi /LAT and MAGIC data is μ VHE = 25 −17 ⁺³⁸ , which is substantially larger than the factor found in the radio band. This suggests one of the source images is strongly affected by microlensing at the moment of the flare. Assuming that the microlensing is produced by a stellar mass object in the lens galaxy, we constrained the size of the emission region in the E > 100 GeV band to be R VHE = 6.6 −5.6 ⁺⁶⁹ × 10 ¹⁴ cm. We note that the spectrum of the microlensed source was unusually hard at the moment of the flare, and we speculate that this hardening may be due to the energy-dependent microlensing effect. This interpretation suggests that the source size decreases with energy in the entire 0.1 − 175 GeV energy range we studied.
