California Institute of Technology

Constraints on the Loss of Hydroperoxymethyl Thioformate (HPMTF) to Marine Clouds Using Aircraft Observations

Abstract The photochemical oxidation of dimethyl sulfide (DMS) by the hydroxyl radical (OH) contributes to the production and growth of particles and cloud condensation nuclei in the marine boundary layer (MBL). DMS oxidized by OH can go on to form a stable intermediate, hydroper...

Growth of aromatic hydrocarbon dust particles in the extremely metal-poor galaxy Sextans A

The mid-infrared spectrum of star-forming, high-metallicity galaxies is dominated by emission features from aromatic and aliphatic bonds in small carbonaceous dust grains, often referred to as polycyclic aromatic hydrocarbons (PAHs). In metal-poor galaxies, the abundance of PAHs...

Early injury responses to nutrient treatment in adult Drosophila limb

It was previously observed that partial regrowth can be induced to begin in adult Drosophila limb by modulating nutrients. In this work, to further investigate the observation, we characterized the early cellular and tissue-level processes that are promoted by nutrient treatment...

Phototropic and skototropic growth in inorganic films

We report herein phototropic growth toward, and skototropic growth away from, an incoherent, unstructured, low-intensity light stimulus in the deposition of nonliving, inorganic material. Fundamental light–matter interactions yield growth of inorganic deposits with ordered mesost...

Regional climate risk assessment from climate models using probabilistic machine learning

Abstract Effective climate risk assessment is hindered by the resolution gap between coarse global climate models and the fine-scale information needed for regional decision making. Existing downscaling methods struggle to bridge this gap: physics-based methods are too computatio...

Electro-optic modulation of coherent and incoherent mid-IR radiation in two-dimensional arrays

Light in the mid-infrared (mid-IR) spans wavelengths from 3 to 8 micrometers and is important to many applications such as gas sensing and thermal imaging. Due to materials challenges, there is now a lack of mid-IR reconfigurable optical elements. Here, we present an electrically...

Universal scaling laws for correlated decay of many-body quantum systems

Abstract Quantum systems are inevitably open, continually exchanging energy and information with the surrounding environment. This interaction leads to decoherence and decay of quantum states. In complex systems, formed by many particles, decay can become correlated and enhanced....

Experimentally Mapping the Phase Diagrams of Photoexcited Small Polarons

Abstract Understanding the fundamental phenomena that dictate photoexcited polarons in materials is critical to tuning their properties. Theoretical models of polarons have only recently been extended to the excited state. Experimental measurements of polaron formation and transp...

SN 2024iss: A Multiwavelength Exposé of a Type IIb Supernova with an Early-time Ultraviolet Spectrum and Shock-breakout Constraints

Abstract We present multiwavelength observations and analysis of SN 2024iss, a Type IIb supernova (SN IIb) located at ∼14 Mpc. The first Zwicky Transient Facility detection of SN 2024iss is ∼40 minutes after first light (one of the earliest detections of a SN IIb to date) and a H...

Influence of Josephson Effect on Proximity Coupled Superconductors

Experimental investigations to examine the influence of Josephson effect on proximity coupled superconductors are reported. The results are interpreted with a proposed physical model that incorporates spatial gradients in both the phase and the amplitude of the proximity induced...

Comparative neuroanatomy of emotion expression: from flies to humans

All animals exhibit complex behaviours that share features with those that in humans we call 'emotional expressions'. Sidestepping contentious issues about the conscious experience of emotion, their expression across species provides a wealth of detail about their emergence in ev...

Line-intensity mapping

Line-Intensity Mapping (LIM) has emerged as a powerful technique for studying large-scale structure and the high-redshift universe, enabling three-dimensional maps of line emission across vast cosmological volumes. In this review, we summarize the LIM framework, its key scientifi...

EZSolver: Template-Free Prediction of Polar Enzymatic Mechanisms via Bidirectional Flow Matching and Search

Abstract Predicting enzymatic reaction mechanisms is critical for understanding enzyme function and for the design and discovery of new enzymes. Current computational predictors rely on deterministic, rule-based dictionaries, which perform well on in-distribution tasks but fail t...

Precision Physics with Muons: A Decade of Theoretical and Experimental Advances

The muon has been instrumental in establishing the Standard Model of particle physics and continues to play a key role in exploring the nature of New Physics. A global program is underway to enhance the discovery potential of a wide range of muon probes, with significant increase...

Rapid data quality investigations of gravitational-wave events with the Data Quality Report Builder toolkit

Abstract We present the Data Quality Report Builder toolkit, DQRbuild, a suite of data quality tools that have been developed to vet gravitational-wave events in preparation for the fourth LIGO-Virgo-KAGRA observing run. We explain the main functionality and the many scientific t...

Gibbs state preparation for commuting Hamiltonian: Mapping to classical Gibbs sampling

Gibbs state preparation, or Gibbs sampling, is a key computational technique extensively used in physics, statistics, and other scientific fields. Recent efforts for designing fast mixing Gibbs samplers for quantum Hamiltonians have largely focused on commuting local Hamiltonians...

GTPase cycle and ER membrane regulate cargo handover during cotranslational protein targeting

Signal recognition particle (SRP), a universally conserved protein-targeting machine, cotranslationally recognizes signal sequences of nascent endomembrane proteins and engages the SRP receptor (SR) at the endoplasmic reticulum (ER) membrane to unload the translating ribosome. Th...

Robust, randomized preconditioning for kernel ridge regression

Abstract We investigate preconditioned conjugate gradient methods for kernel ridge regression (KRR) problems with a moderate to large number of data points ( $$10^4 \le N \le 10^7$$ 10 4 ≤ N ≤ 10 7 ). We develop and analyze two randomized preconditioners with complementary guaran...

Implementation of the Multigrid Gaussian-Plane-Wave Algorithm with GPU Acceleration in PySCF

Abstract We introduce a GPU-accelerated multigrid Gaussian-Plane-Wave density fitting (FFTDF) approach for efficient Fock builds and nuclear gradient evaluations within Kohn–Sham density functional theory, as implemented in the GPU4PySCF module of PySCF. Our CUDA kernels employ a...

The Python simulations of chemistry framework: 10 years of an open-source quantum chemistry project

Over the past decade, the Python-based Simulations of Chemistry Framework (PySCF) has developed into a widely used open-source platform for electronic-structure theory and quantum chemical method development. This article reviews the major advances since the previous overview in...