When Strings Lose Their Gap: Rethinking Confinement
![The relationship between string width and the dimensionless parameter [latex]\alpha = \lambda/\ell[/latex] reveals a convergence of numerical and analytical approaches, with a full numerical solution-depicted as a solid blue curve-supported by analytical approximations (dashed orange and green) valid in the regimes of small and large α, alongside predictions from the EST model (dashed gray).](https://arxiv.org/html/2602.17758v1/x11.png)
New research explores how the absence of a mass gap in bulk theories fundamentally alters the behavior of confining strings and their associated properties.
Science
Seeing the Unseen: Observability in Quantum Dynamics
New research establishes conditions for determining the state of a quantum system governed by the Schrödinger equation, even with incomplete data.
Wormholes and Warnings: Can Gravity Theories Sidestep Time Travel?
![Chronological safety-the absence of closed timelike curves-is demonstrably bounded by parabolic regions defined by spin [latex]\varepsilon_a[/latex], equatorial angle θ, and stellar mass [latex]M_\ast[/latex] when calculations are performed with [latex]M = 1000 M_{Pl}[/latex].](https://arxiv.org/html/2602.17724v1/x6.png)
A new analysis explores how modified gravity theories might avoid the paradoxes of closed timelike curves, and proposes a way to detect causality violations near black holes through gravitational waves.
Seeing Electrons in Motion: How Pulse Shape Impacts Spectroscopy
![With a pulse duration of [latex]\tau = 100\ \mathrm{as}[/latex], the study demonstrates that a cylindrical Gabor transform accurately reconstructs the shape of the energy-momentum spectrum, as evidenced by the near-perfect correspondence between calculated scattering probabilities and the transform’s isolated momentum distributions for a target with [latex]t_d = 0[/latex] and varying transversal widths [latex]\sigma_{\perp}[/latex].](https://arxiv.org/html/2602.18123v1/x3.png)
New research reveals how the size and properties of ultrashort electron pulses affect the precision of electron momentum spectroscopy, impacting our ability to image materials at the atomic scale.
Hunting Shadows: First Results from the Dandelion Dark Matter Search
![The Dandelion experiment, leveraging just 24.7 hours of measurement, establishes a new constraint on the kinetic mixing parameter χ for dark photons with masses between 0.6 and 1.4 meV, assuming these particles comprise the entirety of the local dark matter density of approximately [latex]0.44\,\text{GeV/cm}^{3}[/latex], and thereby defines a boundary beyond which existing theories regarding dark matter interaction must be revised.](https://arxiv.org/html/2602.18218v1/pics/excl.png)
The Dandelion experiment has initiated a new approach to detecting dark matter, focusing on the elusive dark photon and its potential directional signal.
Unlocking Particle Interactions in Confined Spaces
![The analysis of phase shifts-calculated as a function of the coupling constant [latex]CMkk[/latex] for partial waves up to [latex]l=5[/latex]-demonstrates a distinction between spin-up and spin-down states, with the s-wave ([latex]l=0[/latex]) component exclusively residing within the spin-up branch as defined by equations (72) and (73).](https://arxiv.org/html/2602.17924v1/x2.png)
New research provides a refined framework for analyzing particle scattering within the finite volumes used in lattice quantum chromodynamics calculations.
Tuning Materials with Sound: A Faster Path to Alloy Discovery
Resonant ultrasound spectroscopy offers a rapid and non-destructive method for characterizing the mechanical properties of high-entropy alloys, accelerating the search for materials with optimal performance.
Beyond Chance: Measuring the Road to Life
A new framework for quantifying molecular complexity offers a standardized approach to understanding the origins of life on Earth and beyond.
Echoes of Confinement: Unveiling Hidden Dynamics with Krylov Complexity
![Trajectories of [latex]z(t)[/latex] reveal how varying parameters [latex]Q[/latex] influence system behavior, offering a comparative analysis against the established characteristics of the Anti-de Sitter (AdS) case.](https://arxiv.org/html/2602.17757v1/x2.png)
New research demonstrates a striking connection between holographic Krylov complexity and the fundamental scale at which particles become confined within quantum field theories.
Gravity’s Hidden Architecture: How Particles Build Space
![A computational study demonstrates that a system of one thousand particles, all of equal mass, readily converges to a configuration exhibiting minimal variety-a state remarkably close to the absolute minimum of its potential energy landscape [latex]VV[/latex].](https://arxiv.org/html/2602.18115v1/x1.png)
New research reveals that the geometry of self-gravitating systems isn’t fixed, but emerges from the relationships between the particles themselves.