Black Hole Orbits: When Order Descends into Chaos
![Einstein-ModMax black hole parameters are constrained by Event Horizon Telescope shadow observations to a region where shadow radii fall between [latex]4.55[/latex] and [latex]5.22[/latex], effectively excluding parameter spaces outside these bounds and refining the understanding of these complex astrophysical objects.](https://arxiv.org/html/2604.21622v1/x4.png)
New research explores how the energy of charged particles dictates whether their paths around weakly magnetized black holes become predictably stable or wildly chaotic.
Science
Vanishing into the Void: How Potential Wells Shape Unbound Quantum States
![The study of a deeper potential model reveals that wave functions describe both unbound states at energies [latex]E=-0.5593t[/latex] and [latex]E=-0.5568t[/latex], alongside bound states at [latex]E=3.1698t[/latex] and [latex]E=12.8646t[/latex], all within a system size of [latex]L=1597[/latex], demonstrating the delicate balance between confinement and escape inherent in quantum systems.](https://arxiv.org/html/2604.21281v1/x3.png)
New research explores how the depth of potential wells and the introduction of non-Hermitian physics affect the behavior and characteristics of unbound quantum states.
Feeling the Shape of Space: A Quantum Detector’s View
![The equilibrium de-excitation rate, computed from equations (39)-(40), exhibits a dependence on detector acceleration and geometry, demonstrating how variations in parameters [latex]\L_1[/latex], [latex]\L_2[/latex], and α modulate the rate-with the pure Unruh value consistently serving as a limiting case for infinite geometries or specific parameter settings-and revealing a nuanced relationship between acceleration, energy difference [latex]\Delta E[/latex], and the observed de-excitation spectrum across different torus configurations.](https://arxiv.org/html/2604.21118v1/Figure_sect6.png)
New research demonstrates how a quantum detector can reveal the topology of spacetime, potentially identifying exotic geometries like the two-torus.
Echoes of Quark Matter: Can Twin Stars Reveal the Heart of Neutron Stars?
New research leverages Bayesian inference and observations of small, dense stars to explore the possibility of a phase transition to quark matter within neutron stars and the resulting ‘twin star’ phenomenon.
Shaping Molecules with Light
![Calculations employing the QED-UHF method and expansive basis sets-aug-cc-pVTZ and aug-cc-pVQZ-map the potential energy surfaces of cavity-coupled hydrogen rings, demonstrating that the lowest-energy spin state [latex]m_S[/latex] is uniquely determined by both the dimerization angle δ and the strength of magnetic cavity coupling λ, with ground state ring geometries centered on the origin and subjected to a perpendicular quantum magnetic field.](https://arxiv.org/html/2604.20969v1/x2.png)
Researchers are demonstrating how to sculpt molecular potential energy surfaces using magnetic cavity quantum electrodynamics, opening new avenues for controlling chemical reactions and material properties.
Dark Matter’s Hidden Link to Baryon Asymmetry
![The search for weakly interacting massive particles-specifically, those decaying via a hidden sector with a scale [latex]\Lambda_{n}[/latex]-reveals a parameter space tightly constrained by both cosmological observations and collider experiments; Big Bang nucleosynthesis and cosmic microwave background data exclude regions where particle decay disrupts primordial element abundances, while searches at CHARM, NA62, and SHiP progressively narrow the viable range, permitting only short-lived ([latex]\tau_{\chi} \lesssim 0.1\,{\rm s}[/latex]) or exceedingly long-lived ([latex]\tau_{\chi} \gtrsim 10^{25}\,{\rm s}[/latex]) particles, or those with a hidden sector scale between 2 and 100 TeV if decaying before the era of nucleosynthesis.](https://arxiv.org/html/2604.21168v1/LT4.png)
A new model proposes a connection between dark matter, the imbalance between matter and antimatter, and a fundamental ‘neutron portal’ interaction.
Beyond Hermiticity: Integrability in Quantum Impurity Systems
![The study demonstrates that the phase structure of an effective pseudo-Hermitian impurity Hamiltonian-defined by parameters γ and β-undergoes a transition at [latex]\beta = \gamma[/latex], demarcating a region where complex conjugate pairs of Bethe rapidities emerge, ultimately coalescing into a double real root at the exceptional point and manifesting as a shift in resolvent behavior from simple-pole ([latex]\|R(z)\| \sim \delta^{-1}[/latex]) to second-order pole ([latex]\|R(z)\| \sim \delta^{-2}[/latex]) characteristics that underpin both pseudospectrum scaling and diagnostics via the Gaudin matrix.](https://arxiv.org/html/2604.21547v1/x1.png)
New research reveals how integrability-a powerful tool for solving complex quantum problems-persists even in non-Hermitian systems exhibiting exceptional points.
Rewriting Quantum Gravity: A Geometrically Grounded Path
A new approach to quantizing gravity leverages the Dressing Field Method to automatically resolve anomalies and establish a manifestly relational, gauge-invariant framework.
Rewriting Gravity: A New Look at Cosmic Expansion
![Effective frequency [latex]\omega_{eff}[/latex] shifts in relation to the variable [latex]z[/latex].](https://arxiv.org/html/2604.21151v1/x3.png)
Researchers are exploring modified gravity theories, specifically f(Q,T) gravity coupled with an affine equation of state, to explain the accelerating expansion of the universe.
Lost in Translation: How Decoherence Could Blur the View of Future Neutrino Experiments
A new analysis reveals that different methods for modeling quantum decoherence can dramatically alter the precision with which upcoming long-baseline neutrino experiments will determine fundamental neutrino properties.