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Comprehensive Ab Initio Quantum Computations of CO$_{\rm 2}$-H$_{\rm 2}$ and CO$_{\rm 2}$-He Collisional Properties

Announce Type: replace Abstract: We present comprehensive \textsl{ab initio} fully quantum calculations of CO$_{\rm 2}$--H$_{\rm 2}$ and CO$_{\rm 2}$--He collisional properties. Our framework combines CCSD(T) potential-energy-surface calculations with close-coupling dynamical scattering in the \YUMI~framework to derive elastic and inelastic cross sections, rate coefficients, and pressure broadening parameters. We characterize the rotational dependence of the broadening coefficients up to...

arXiv Physics 5d ago

$H_2$ optimal model reduction of linear systems with multiple quadratic outputs

Announce Type: replace Abstract: In this work, we consider the $H_2$ optimal model reduction of dynamical systems that are linear in the state equation and up to quadratic nonlinearity in the output equation. As our primary theoretical contributions, we derive gradients of the squared $H_2$ system error with respect to the reduced model quantities and, from the stationary points of these gradients, introduce Gramian-based first-order necessary conditions for the $H_2$ optimal approximation...

arXiv CS 7d ago

$\mathcal{H}_2$-optimal model reduction of linear quadratic-output systems by multivariate rational interpolation

Announce Type: replace Abstract: This paper addresses the $\mathcal{H}_2$-optimal approximation of linear dynamical systems with quadratic-output functions, also known as linear quadratic-output systems. Our major contributions are threefold. First, we derive interpolatory first-order optimality conditions for the linear quadratic-output $\mathcal{H}_2$ minimization problem.

arXiv CS 6d ago

Valence Ionization Of Water Clusters Formed Inside Helium Nanodroplets

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arXiv Physics 7d ago

Collisional excitation of H$_2$CO by He: Experimental validation of state-of-the-art scattering calculations

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arXiv Physics 2d ago

Spin dynamics and ortho-para conversion in H$_{2}$O at the gas-ice phase transition in external magnetic fields

arXiv:2606.04242v1 Announce Type: new Abstract: The spin dynamics of water ice in the presence of external magnetic fields are investigated. The employed model builds upon the approach introduced by Buntkowsky et al.

arXiv Physics 6d ago

Late-Time Cosmology and Structure Formation in Quadratic $f(Q)$ Gravity

arXiv:2606.02660v1 Announce Type: new Abstract: We investigate the cosmological evolution associated with the quadratic symmetric teleparallel gravity framework, \( f(Q)=Q+\alpha Q^{2}+\beta \) where the relation \(Q\propto H^{2}\) generates an additional \(H^{4}\) contribution to the Friedmann equation. Using the exact algebraic solution for $H(z)$, we reconstruct the effective dark-energy sector and compare the background evolution with $\Lambda$CDM using Type Ia supernovae, BAO, and...

arXiv Physics 7d ago

A first-in-class pulsatile FXR agonist for bile-acid-related liver diseases

Abstract Nuclear receptors are central regulators of metabolism1, yet therapeutic strategies that enforce continuous receptor activation frequently lead to reduced efficacy and unacceptable toxicity. Here we report a first-principles drug design strategy that aligns pharmacokinetics with physiological signalling cycles. We developed linafexor, a potent non-bile-acid agonist of the farnesoid X receptor (FXR)2; it is engineered for rapid systemic clearance, which enables pulsatile receptor...

Nature 20h ago

Expressibility, Noise, and Error Mitigation in VQE Ansatz Selection

arXiv:2606.04955v1 Announce Type: cross Abstract: The variational quantum eigensolver (VQE) is a promising algorithm for near-term quantum chemistry applications, but selecting optimal ansatz circuits remains challenging. Expressibility, a metric quantifying a circuit's ability to explore the Hilbert space, has been proposed as a guide for ansatz selection, but recent work showed it inconsistently predicts VQE performance under realistic noise for $H_2$. We extend this investigation to cover...

arXiv CS 6d ago

A cryogenic gas target for high-intensity radioactive ion beam production at HIRFL-RIBLL

arXiv:2606.04139v1 Announce Type: new Abstract: A liquid-nitrogen-cooled cryogenic gas target system has been developed and installed for radioactive ion beam (RIB) production at the Radioactive Ion Beam Line in Lanzhou (RIBLL). Light element gases ($\mathrm{H_2}$, $\mathrm{D_2}$, and $\mathrm{^4He}$) filled in the target cell were cooled to approximately 82-86 K with pressures up to 1000 mbar. Utilizing this target, high-quality $^{7}\mathrm{Be}$, $^{16}\mathrm{N}$, and $^{15}\mathrm{O}$...

arXiv Physics 6d ago