Hasil untuk "Physics"

Xiaodong Xu, W. Yao, Di Xiao et al.

Y. Shnir

A. Kamenev

The physics of non-equilibrium many-body systems is a rapidly expanding area of theoretical physics. Traditionally employed in laser physics and superconducting kinetics, these techniques have more recently found applications in the dynamics of cold atomic gases, mesoscopic and nano-mechanical systems, and quantum computation. This book provides a detailed presentation of modern non-equilibrium field-theoretical methods, applied to examples ranging from biophysics to the kinetics of superfluids and superconductors. A highly pedagogical and self-contained approach is adopted within the text, making it ideal as a reference for graduate students and researchers in condensed matter physics. In this Second Edition, the text has been substantially updated to include recent developments in the field such as driven-dissipative quantum systems, kinetics of fermions with Berry curvature, and Floquet kinetics of periodically driven systems, among many other important new topics. Problems have been added throughout, structured as compact guided research projects that encourage independent exploration.

J. Bekenstein

There are a number of similarities between black-hole physics and thermodynamics. Most striking is the similarity in the behaviors of black-hole area and of entropy: Both quantities tend to increase irreversibly. In this paper we make this similarity the basis of a thermodynamic approach to black-hole physics. After a brief review of the elements of the theory of information, we discuss black-hole physics from the point of view of information theory. We show that it is natural to introduce the concept of black-hole entropy as the measure of information about a black-hole interior which is inaccessible to an exterior observer. Considerations of simplicity and consistency, and dimensional arguments indicate that the black-hole entropy is equal to the ratio of the black-hole area to the square of the Planck length times a dimensionless constant of order unity. A different approach making use of the specific properties of Kerr black holes and of concepts from information theory leads to the same conclusion, and suggests a definite value for the constant. The physical content of the concept of black-hole entropy derives from the following generalized version of the second law: When common entropy goes down a black hole, the common entropy in the black-hole exterior plus the black-hole entropy never decreases. The validity of this version of the second law is supported by an argument from information theory as well as by several examples.

P. Peebles, Bharat Ratra

Physics invites the idea that space contains energy whose gravitational effect approximates that of Einstein's cosmological constant, Lambda: nowadays the concept is termed dark energy or quintessence. Physics also suggests the dark energy could be dynamical, allowing the arguably appealing picture that the dark energy density is evolving to its natural value, zero, and is small now because the expanding universe is old. This alleviates the classical problem of the curious energy scale of order a millielectronvolt associated with a constant Lambda. Dark energy may have been detected by recent advances in the cosmological tests. The tests establish a good scientific case for the context, in the relativistic Friedmann-Lemaitre model, including the gravitational inverse square law applied to the scales of cosmology. We have well-checked evidence that the mean mass density is not much more than one quarter of the critical Einstein-de Sitter value. The case for detection of dark energy is serious but not yet as convincing: we await more checks that may come out of work in progress. Planned observations might be capable of detecting evolution of the dark energy density: a positive result would be a considerable stimulus to attempts to understand the microphysics of dark energy. This review presents the basic physics and astronomy of the subject, reviews the history of ideas, assesses the state of the observational evidence, and comments on recent developments in the search for a fundamental theory.

L. J. Bellamy

A. Altland, Ben D. Simons

The methods of quantum field theory underpin many conceptual advances in contemporary condensed matter physics and neighbouring fields. This book provides a praxis-oriented and pedagogical introduction to quantum field theory in many-particle physics, emphasizing the application of theory to real physical systems. This third edition is organized into two parts: the first half of the text presents a streamlined introduction, elevating readers to a level where they can engage with contemporary research literature, from the introduction of many-body techniques and functional integration to renormalization group methods, and the second half addresses a range of advanced topics including modern aspects of gauge theory, topological and relativistic quantum matter, and condensed matter physics out of thermal equilibrium. At all stages, the text seeks a balance between methodological aspects of quantum field theory and practical applications. Extended problems with worked solutions provide a bridge between formal theory and a research-oriented approach.

E. Runge, E. Gross

R. N. Haward, R. E. Robertson

R. Smith

F. Spiers

J. Cowie

R. R. Rogers, M. Yau, R. R. Rhodes et al.

V. Vladimirov

H. Granicher, F. Jona

P. Sakic, P. Boissier, P. Boissier et al.

<p>In recent years, the field of geodetic monitoring is undergoing a profound transformation driven by the transition from GPS-only positioning to a fully multi-GNSS environment. With Galileo, BeiDou, and modernized GPS &amp; GLONASS constellations now operational, a wealth of new signals and frequencies provides enhanced opportunities for high-precision positioning and real-time monitoring. However, these advances present challenges: the integration of heterogeneous receivers across local and campaign-based networks, the continued reliance on outdated RINEX 2 workflows, and the discontinuation of the <code>teqc</code> utility in 2019 have all disrupted well proven, long-standing GNSS pre-processing pipelines. While the <i>International GNSS Service</i> (IGS) community has smoothly adopted RINEX <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">3</mn><mo>/</mo><mn mathvariant="normal">4</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="260af46f346b63c527387f7858f175c2"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gi-15-89-2026-ie00001.svg" width="20pt" height="14pt" src="gi-15-89-2026-ie00001.png"/></svg:svg></span></span> and alternative pre-processing tools, smaller research-oriented networks have often struggled to keep pace, leaving a gap between available technology and operational monitoring practices.</p> <p>In this paper, we present two complementary tools designed to address these challenges in the context of volcanological and seismological observatories. The first, <code>rinexmod</code> (for <i>RINEX Modification</i>), is a lightweight utility for editing RINEX headers, renaming files, and enriching metadata. It replaces critical <code>teqc</code> functionalities while supporting modern RINEX <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">3</mn><mo>/</mo><mn mathvariant="normal">4</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="eb581bee290aca91043393d5ba11d8f5"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gi-15-89-2026-ie00002.svg" width="20pt" height="14pt" src="gi-15-89-2026-ie00002.png"/></svg:svg></span></span> conventions, long-file naming schemes, and direct sitelog integration. The second, <code>autorino</code> (for <i>Assisted Unloading, Treatment and Organization of RINEX Observations</i>), implements a flexible multi-step workflow for automated acquisition of raw GNSS data from heterogeneous receivers and conversion to a common standard RINEX format. By integrating official manufacturer converters, handling file splicing/splitting, and linking directly with <code>rinexmod</code>, it provides a unified pipeline capable of near real-time operation (down to 5-minute intervals). Together, these tools modernize GNSS workflows across networks that are both technically diverse and geographically remote, ensuring interoperability with IGS standards while preserving operational robustness in challenging field conditions.</p> <p>We illustrate their deployment at the <i>Institut de physique du globe de Paris</i>’s volcanological observatories and monitoring networks in Guadeloupe, Martinique, La Réunion, and Mayotte, where they enable continuous monitoring of volcanic and tectonic processes. Beyond local applications, these tools contribute to bridging the gap between global GNSS standards and regional network realities, supporting the long-term sustainability of GNSS-based geo-hazard monitoring.</p>

Agung Riyanto Budi Santoso, Respati Suryanto Dradjat, Edi Mustamsir et al.

Aim Orthopedic implants must meet specific criteria, including mechanical strength, durability, and biocompatibility. This study compares the immune response of zirconia, polyether ether ketone (PEEK), and stainless-steel implants in vivo, focusing on lymphocyte and fibroblast infiltration as indicators of immune activation. Methods A total of 27 New Zealand white rabbits were used, with nine animals in each group. Implants of zirconia, PEEK, or stainless steel were surgically placed in the thigh and observed for 4 weeks. Histological analysis measured lymphocyte and fibroblast infiltration at the implant site using a microscope at 400x magnification. Statistical analysis included the Kruskal-Wallis test for group comparisons, followed by Mann-Whitney and Bonferroni correction for pairwise comparisons. Results The Kruskal-Wallis test showed significant differences in lymphocyte (p=0.002) and fibroblast (p=0.003) counts among the groups. Zirconia exhibited significantly lower lymphocyte (median=0.5) and fibroblast (median=1.0) infiltration compared to stainless steel (lymphocytes: median=3.0, fibroblasts: median=2.0), and PEEK (lymphocytes: median=2.0, fibroblasts: median=3.0). Bonferroni correction confirmed zirconia showed the least immune activation (p&lt;0.0167). Conclusion Zirconia offers superior biocompatibility with minimal immune response, making it an ideal material for orthopedic implants, particularly for patients with metal sensitivities. PEEK showed moderate immune activation but is helpful for non-load-bearing applications. Stainless Steel induced the highest immune response due to the release of metal ions and corrosion. Zirconia is the most biocompatible material tested, making it a promising choice for orthopedic implants.

D. Morrill, W. Hettel, D. Carlson et al.

High-harmonic upconversion driven by a mid-infrared femtosecond laser can generate coherent soft x-ray beams in a tabletop-scale setup. Here, we report on a compact ytterbium-pumped optical parametric chirped pulse amplifier (OPCPA) laser system seeded by an all-fiber front-end and employing periodically poled lithium niobate (PPLN) nonlinear media operated near the pulse fluence limits of current commercially available PPLN crystals. The OPCPA delivers 3 µm wavelength pulses with 775 µJ energy at 1 kHz repetition rate, with transform-limited 120 fs pulse duration, diffraction-limited beam quality, and ultrahigh 0.33% rms energy stability over >18 h. Using this laser, we generate soft x-ray high harmonics (HHG) in argon gas by focusing into a low-loss, high-pressure gas-filled anti-resonant hollow core fiber (ARHCF), generating coherent light at photon energies up to the argon L-edge (250 eV) and carbon K-edge (284 eV), with high beam quality and ∼1% rms energy stability. This work demonstrates soft x-ray HHG in a high-efficiency guided-wave phase matched geometry, overcoming the high losses inherent to mid-IR propagation in unstructured waveguides, or the short interaction lengths of gas cells or jets. The ARHCF can operate in the long term without damage and with the repetition rate, stability, and robustness required for demanding applications in spectromicroscopy and imaging. Finally, we discuss routes for further optimizing the soft x-ray HHG flux by driving He at higher laser intensities using either the signal (1.5 μm) or idler wavelengths (3 μm).

Oscar Fuentealba, Iva Lovrekovic, David Tempo et al.

Abstract An enhanced version of the conformal BMS3 algebra is presented. It is shown to emerge from the asymptotic structure of an extension of conformal gravity in 3D by Pope and Townsend that consistently accommodates an additional spin-2 field, once it is endowed with a suitable set of boundary conditions. The canonical generators of the asymptotic symmetries then span a precise nonlinear W(2,2,2,2,1,1,1) algebra, whose central extensions and coefficients of the nonlinear terms are completely determined by the central charge of the Virasoro subalgebra. The wedge algebra corresponds to the conformal group in four dimensions SO(4, 2) and therefore, enhanced conformal BMS3 can also be regarded as an infinite-dimensional nonlinear extension of the AdS5 algebra with nontrivial central extensions. It is worth mentioning that our boundary conditions might be considered as a starting point in order to consistently incorporate either a finite or an infinite number of conformal higher spin fields.

Fei Gao, Julia Harz, Chandan Hati et al.

Abstract A large primordial lepton asymmetry can lead to successful baryogenesis by preventing the restoration of electroweak symmetry at high temperatures, thereby suppressing the sphaleron rate. This asymmetry can also lead to a first-order cosmic QCD transition, accompanied by detectable gravitational wave (GW) signals. By employing next-to-leading order dimensional reduction we determine that the necessary lepton asymmetry is approximately one order of magnitude smaller than previously estimated. Incorporating an updated QCD equation of state that harmonizes lattice and functional QCD outcomes, we pinpoint the range of lepton flavor asymmetries capable of inducing a first-order cosmic QCD transition. To maintain consistency with observational constraints from the Cosmic Microwave Background and Big Bang Nucleosynthesis, achieving the correct baryon asymmetry requires entropy dilution by approximately a factor of ten. However, the first-order QCD transition itself can occur independently of entropy dilution. We propose that the sphaleron freeze-in mechanism can be investigated through forthcoming GW experiments such as μAres.