A central question in strong-interaction physics, governed by quantum chromodynamics (QCD), is whether femtoscale droplets of quark-gluon plasma form in small collision systems involving projectiles significantly smaller than heavy ions. Collisions of light ions such as ^{16}O and ^{20}Ne offer a unique opportunity to probe the emergence of collective behavior in QCD matter. This Letter presents the first measurements of the elliptic (v_{2}) and triangular (v_{3}) flow of charged particles in ^{16}O-^{16}O and ^{20}Ne-^{20}Ne collisions at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.36 TeV with the ALICE detector. The hydrodynamic model predictions, explicitly incorporating the nuclear structures of ^{16}O and ^{20}Ne, exhibit a good agreement with the flow measurements presented. The observed increase of v_{2} in central Ne-Ne collisions relative to OO collisions, driven by the nuclear geometries, highlights the importance of utilizing light nuclei with well-defined geometric shapes to constrain the initial conditions. These findings support the presence of nuclear geometry-driven hydrodynamic flow in light-ion collisions at the LHC.
We investigate the microscopic properties of the kagome compound Cs_{2}Cu_{3}SnF_{12} using ^{63,65}Cu nuclear quadrupolar resonance. Analysis of the local hyperfine fields below the Néel temperature T_{N}=20 K indicates a spin structure consistent with P2_{1}/n symmetry of negative vector chirality. Measurements of the spin-lattice relaxation rate T_{1}^{-1} reveal signatures of a gapless ground state and two-dimensional Berezinskii-Kosterlitz-Thouless-type correlations above T_{N}, extending over a broad temperature range of approximately 130 K in zero magnetic field. Within the same temperature range, the observed increase in the nuclear quadrupolar resonance linewidth is consistent with short-range chiral order recently identified by neutron scattering. Our results establish Cs_{2}Cu_{3}SnF_{12} as a unique quantum kagome system exhibiting Berezinskii-Kosterlitz-Thouless behavior.
We develop a consistent partially off-shell framework for evaluating higher-derivative actions of five-dimensional N=1 gauged supergravity with Abelian vector multiplets on AdS_{5}. Using the superconformal formalism, we show that the resulting holographic expression reproduces the trial a-anomaly coefficient of the dual conformal field theory, identifying the supergravity equations of motion with a maximization. We present an exact correspondence between Chern-Simons couplings and the anomaly polynomial of the boundary theory. We illustrate our proposal by applying it to all known two- and four-derivative actions, including the "off-diagonal" invariants never before considered in the gauged supergravity literature. Finally, we argue that all invariants beyond four derivative yield no genuinely new contributions to asymptotically AdS_{5} BPS backgrounds, but instead reduce to linear combinations of the established two- and four-derivative actions.
Isotopic measurements of presolar silicon carbide grains from dying stars have revealed a puzzling overabundance of ^{94}Mo that stellar nucleosynthesis models have failed to reproduce for two decades. This discrepancy challenged our understanding of the slow neutron-capture process (s-process) that forges approximately half of the elements heavier than iron. The key uncertainty lies at ^{94}Nb, a radioactive branching point where competition between neutron capture and beta decay governs the ^{94}Mo production, yet the neutron-capture cross section had never been measured. Here, we report the first experimental determination of the ^{94}Nb(n,γ)^{95}Nb cross section important for Mo isotopic abundances. The measurement was enabled by a coordinated effort involving high-purity target preparation at Institute of Solid State and Materials Research Dresden, radioactive sample production at the Institut Laue-Langevin Grenoble, radiochemical characterization at Paul Scherrer Institut Villigen, and the time-of-flight CERN n_TOF facility using for the first time segmented total-energy detectors. Incorporation of the resulting Maxwellian-averaged cross section into fully coupled nucleosynthesis models of low-mass asymptotic giant-branch stars brings them into agreement with the presolar grain data. These results remove a major nuclear-physics input uncertainty at the ^{94}Nb branching point and provide a firmer foundation for understanding the origin of ^{94}Mo in the Solar System.
Spin-triplet topological superconductors are rare but of fundamental interest as they can host Majorana bound states that can be used in fault-tolerant quantum computing. Recent efforts have been devoted to searching for spin-triplet states in U-based compounds, but these materials have a low transition temperature (T_{c}) and coexisting competing orders, which creates significant experimental challenges and often leads to contradictory conclusions. The Cr-based candidate K_{2}Cr_{3}As_{3} offers a promising alternative: it has a much higher T_{c}≥6.2 K and no magnetic order. Here we report a hallmark signature of spin-triplet superconductivity arising from the internal spin degrees of freedom via nuclear magnetic resonance measurements, and demonstrate the high tunability of the topological phases. We discovered three distinct superconducting phases and revealed the evolution of the paired-spins direction [d(k)-vector]. At low magnetic fields, K_{2}Cr_{3}As_{3} evolves from a helical (Phase A) to a chiral state (Phase B) with a rotation of the d(k)-vector from in-plane to out-of-plane direction upon cooling, although both phases have point nodes in the gap. A line-nodal gap is realized in the high-field Phase C, where the d(k)-vector lies in the basal plane. These findings establish K_{2}Cr_{3}As_{3} as a model spin-triplet superconductor and a promising platform for manipulating topological phases.
We apply harmonic analysis to study the TT[over ¯]-deformed torus partition function. We first express the CFT partition functions in terms of Maass waveforms, including the Eisenstein series and cusp forms. These basis functions turn out to deform in a very simple way under the TT[over ¯] deformation. The spectral decomposition provides a numerically stable and efficient method to compute the partition function at finite values of the deformation parameter λ, allowing us to clearly resolve the analytic structure of the partition function as a function of λ. The resulting deformed partition function exhibits a Hagedorn singularity. Building on the harmonic analysis approach, we propose a natural analytic continuation beyond the Hagedorn singularity, which enables us to compute the full partition function for any value of λ.
This Letter presents a lattice quantum chromodynamics (QCD) determination of π π π scattering amplitudes for the isospin-2 channel with angular momentum and parity J P = 1 + . The calculation is performed using unphysically heavy light-quark masses, corresponding to a pion mass of m π ≈ 400 MeV , for which the ρ meson manifests as a narrow resonance. The analysis employs a previously developed formalism that nonperturbatively relates the finite-volume spectra of two- and three-pion systems to their infinite-volume scattering amplitudes. We combine earlier lattice QCD results for π π systems with isospins 1 and 2 with new determinations of the isospin-2 three-pion finite-volume spectrum, obtained for three cubic, periodic lattice volumes with box length ranging from ≈ 4 / m π to 6 / m π . These combined data constrain the low-lying partial waves of the infinite-volume three-pion K matrix, from which we solve a set of coupled integral equations to extract the corresponding scattering amplitudes.
Nonreciprocal interactions in active matter give rise to a multitude of fascinating phenomena among which are collective oscillatory states without intrinsic particle chirality and active turbulence. Here we show that, in a paradigmatic model for nonreciprocal flocking, the two-species Vicsek model, these two states coexist: chiral order for small flocks and extensive spatiotemporal chaos for large flocks, both separated by a finite-wavelength instability whose scale is set by the rotation radius of the chiral orbits. For system sizes larger than this length scale extensive spatiotemporal chaos unfolds, as manifested by an extensive number of positive Lyapunov exponents as well as of Floquet exponents, a finite correlation and chaotic length, and a broad energy spectrum. Our results suggest that complex, turbulent behavior is a generic possibility in systems where particles or fields interact asymmetrically and may have significant implications for understanding how nonreciprocal interactions could drive chaotic, fluidlike behavior in active matter.
We detect entanglement partitions of multipartite quantum systems by exploiting their inherent symmetries. Structures like genuinely multipartite entanglement, m -separability, and entanglement depth are detected as very special cases. This formulation enables us to characterize all entanglement partitions of all three- and four-partite states and witnesses with unitary and permutation symmetry, which we denote Schur-Weyl isotypic witnesses. In particular, we find and parametrize a complete set of bound entangled states therein. For larger systems, we provide a large family of analytical witnesses detecting multipartite states of arbitrary size where none of the parties is separable from the rest. The proposed method relies on weak Schur sampling with projective measurements onto isotypic components and can be implemented in a quantum computer. Beyond physics, our results extend to the mathematical literature: we establish new inequalities between matrix immanants, which constitute an open problem, and characterize the set of such inequalities for matrices of sizes three and four.
We present the thermopower of EuCd 2 P 2 , a material which exhibits a large resistivity peak with significant magnetic field dependence in the temperature range of 10–25 K. In the same region, we observe a highly unusual behavior of the thermopower with two sign changes and giant extrema. The overall variation of the thermopower exceeds 4000 μ V / K and takes place in an extremely narrow temperature region of less than 5 K. The anomaly is suppressed completely in a small magnetic field of 0.5 T. We discuss this observation using a simple drift-diffusion picture and taking into account that the temperature gradient inducing the thermopower voltage is accompanied by a gradient of the electrical resistivity. Our simple estimation yields the correct magnitude, shape, and field dependence of the thermopower anomaly observed in EuCd 2 P 2 . These results open a new route to giant thermopower values via gradients of electronic properties.
Laser wakefield accelerators are bright, compact sources of synchrotronlike x-rays. By driving the wakefield using a 110 TW laser in a variable length gas cell, we are able to map the evolution of the electron beam and resulting x-ray emission. We find that using a laser pulse initially focused to larger than the matched spot size and extending the plasma length beyond the depletion length, dramatically increases the x-ray flux. Self-injected electrons are initially accelerated to > 2 GeV , emitting x-rays with critical energy E c > 20 keV . But, as these electrons dephase, a second high-charge electron bunch is produced and accelerated to ≈ 0.7 GeV . The x-rays produced by this bunch dominate the total emission with > 5 × 10 10 photons per shot with E c = 12 – 17 keV and a flux of 7 × 10 4 photons / mrad 2 / 0.1 % BW . Combining electron and x-ray measurements reveals that the increased emission results from the larger betatron amplitude of the secondary bunch. Simulations attribute this to rapid bubble expansion driven by laser compression over the depletion length, which leads to injection of a high-charge electron bunch with increased transverse momentum and thus stronger betatron radiation.
A search for Higgs boson ( H ) production in association with two vector bosons ( V = W , Z ) via vector-boson scattering (VBS) is presented using proton-proton collision data collected at s = 13 TeV by the CMS experiment, corresponding to an integrated luminosity of 138 fb − 1 . Events containing two forward jets consistent with VBS, a large-radius jet from the decay of a boosted H to a pair of b quarks, and zero, one, or two charged leptons coming from V decays are selected. The process is excluded at 95% confidence level for observed (expected) values of the V V H H coupling modifier κ 2 V outside the interval 0.40 < κ 2 V < 1.60 ( 0.34 < κ 2 V < 1.66 ), assuming standard model values for all other couplings, thus establishing a novel probe of the V V H H interaction. Constraints are also set on the individual κ 2 W and κ 2 Z coupling modifiers and on the allowed region in the κ 2 W − κ 2 Z plane.
