Quantum Fisher information and photon statistics from shift current shot noise.

October 13, 2026| Source: Proceedings of the National Academy of Sciences of the United States of America

Quantum Fisher information (QFI) sets the ultimate precision of optical phase measurements and can reveal multiphoton entanglement. Yet the photon-number fluctuations that encode this sensitivity are difficult to convert into an electrical signal. We theoretically predict that a photodetector utilizing the shot noise of the quantum-geometric shift current of exciton polaritons can measure photon-number statistics and, for pure states, infer the QFI. By solving the Lindblad equation, we obtain the time-dependent nonlinear photocurrent for an arbitrary initial photon state. It turns out that, regardless of the quantum state of the incident light, the integrated current depends only on the mean photon number. In contrast, the shot noise retains information about photon-number fluctuations: Its Fano factor is proportional to the photon-number variance. Numerical calculations confirm these relations for optical Schrödinger cat and squeezed-vacuum states. A photodetector based on shift current noise can therefore provide a solid-state platform for high-precision measurements of quantum-optical statistics without relying on mobile photocarriers.

Read the original source →

Reaction-based cryo-EM resolves the continuous conformational spectrum of CTP synthase catalysis.

Capturing enzymes under native turnover conditions remains a grand challenge in structural biology. Here, we develop a reaction-based cryo-electron microscopy (cryo-EM) strategy that directly samples Drosophila melanogaster cytidine triphosphate synthase (CTPS) from actively catalyzing mixtures containing only natural substrates and allosteric effectors. By integrating reaction-based sampling with three-dimensional variability analysis, we resolve a continuous conformational spectrum of CTPS dur

Physical/TechOctober 20, 2026

GTP orchestrates CTP synthase via an allosteric effector-cycling mechanism.

Cytidine triphosphate (CTP), a fundamental building block of RNA, plays vital roles in diverse biological processes. CTP synthase (CTPS) is the only known enzyme for de novo synthesis of CTP. Efficient CTPS catalysis requires guanosine triphosphate (GTP) in a dose-dependent, nonconsumptive manner; however, the precise mechanism by which GTP drives CTP formation remains unclear. Here, we integrate a series of cryo-EM structures of Drosophila melanogaster CTPS captured from actively catalyzing sam

Physical/TechOctober 13, 2026

Convergent innovation of (crypto)vivipary via asymmetric dismantling of seed desiccation and dormancy machinery.

Cryptovivipary and vivipary, referred to as (crypto)vivipary, occur across multiple angiosperm lineages and enable embryos to continue developing before dispersal. Yet, this trait raises a fundamental question: how are seed-specific abscisic acid (ABA) responses modulated to support continuous embryonic growth without compromising ABA-dependent vegetative stress tolerance? Here, integrating phylogenomic analyses of independently evolved (crypto)viviparous lineages with spatiotemporal transcripto

Physical/TechOctober 13, 2026

The Benjamini-Hochberg procedure can fail to control the FDR for correlated two-sided Gaussian tests.

The Benjamini-Hochberg (BH) procedure is the standard method for controlling the false discovery rate (FDR) in large-scale studies involving testing multiple hypotheses. Whether the BH procedure controls the FDR for every correlation structure among two-sided Gaussian tests has been a long-standing question, and a positive answer has been believed. Here, we settle the question negatively, by providing examples of Gaussian factor models for which the BH method fails to control the FDR at the nomi

Physical/TechOctober 13, 2026

NA-CDQuant: Quantitative spectral analysis of nucleic acid structure by circular dichroism spectroscopy.

Understanding the structural conformation and dynamics of nucleic acids in solution is critical for the development of nucleic acid therapeutics involving antisense or mRNA therapies, where controlling stability, efficacy, and manufacturability are important. Circular dichroism (CD) spectroscopy allows rapid and nondestructive solution analysis of the spatial arrangements of nucleic acids. While widely used to analyze protein structure, the potential of CD for DNA- and RNA-based pharmaceutical a