New papers on Quantum physics & computing
380 new papers on quantum physics & computing in the last 7 days, within Physics. These are the 50 Pipette rates most worth reading, with the main result in the authors' own words.
The best of the week
In-orbit operation of a programmable quantum photonic processor
Here, we report a programmable quantum photonic platform operating on a nanosatellite, processing two photons in a six-mode universal integrated circuit.
PreprintClaims a big stepReal-world usePersistent Quantum-Enhanced Frequency Sensing with T^{-3/2} Scaling
Here, we restore persistent quantum advantage by embedding Fock-state enhancement within a quantum heterodyne (Qdyne) protocol, decoupling sensitivity from the decoherence-limited interrogation time {\tau}.
PreprintClaims a big stepStrong coupling of a reconfigurable Yb atom array to a tunable telecom-band nanofiber cavity
Here, we realize strong atom-cavity coupling on the transition of , establishing, to our knowledge, the first neutral-atom cavity-QED system to reach the single-atom strong-coupling regime on a telecom-band atomic transition.
PreprintClaims a big stepNonlocal advantage of quantum coherence in tau-lepton pairs from electron--positron collisions
Unlike other systems, tau-lepton pair () production in electron--positron () collisions provides an ideal testing ground, as it exhibits strong quantum correlations and, in particular, NAQC over a large region of phase space.
PreprintClaims a big stepA photonic integrated comb engine for ultracold quantum gases
Here we demonstrate a scalable, hybrid-integrated microcomb engine at 780 nm that seamlessly bridges frequency synthesis, atomic referencing and power amplification to achieve quantum state control of a Bose--Einstein condensate.
PreprintBold claims, read criticallyClaims a big stepBosonic Error Correction with Fluxonium
These results provide the first demonstration of resonator control using a weakly coupled fluxonium and, with it, the first realization of standalone bosonic QEC in a fully planar superconducting circuit architecture.
PreprintClaims a big stepBridge of 's: Quantum Circuit Optimization with Schr\"odinger Bridges
On held-out 8 qubits 64 depth Clifford+ circuits, BOPS reduces gate count by and depth by in geometric mean, outperforming all nine baseline optimizers.
PreprintBold claims, read criticallyClaims a big stepReal-world useDeterministic photon waveform adaptation for quantum connectivity
Here we demonstrate a cold-atom optical quantum memory that simultaneously achieves near-unity storage-and-retrieval efficiency and deterministic temporal adaptation of single photons between arbitrary and programmable input and output pulse waveforms.
PreprintClaims a big stepModular fault-tolerant quantum computing on a non-CSS code
In this work, we implement for the first time all logical operations required for modular fault-tolerant universal quantum computing with a non-Calderbank-Shor-Steane (CSS) code, the perfect code, on a trapped-ion quantum computer.
PreprintClaims a big stepQuantum Advantage for Distributed Symmetry Breaking
We present a distributed quantum algorithm that -colors cycles in rounds, with high probability.
PreprintClaims a big stepDense pentacene cocrystal demonstrates room-temperature coherent control
Despite this density, DHP/Pc exhibits microsecond spin coherence, room-temperature optically detected magnetic resonance and coherent control.
PreprintThermodynamic Proof of Quantumness without Structure
Thus, in the random-oracle setting, sufficiently low energy consumption in a successful implementation certifies quantumness through a macroscopic thermodynamic observation of energy consumption.
PreprintQuantum computational advantage in random-circuit sampling on IBM superconducting quantum computers
To our knowledge, this is the first demonstration of quantum advantage for a vanilla random-circuit sampling on a commercially and broadly accessible quantum processor that most non-expert quantum computer users can easily replicate.
PreprintBold claims, read criticallyClaims a big stepActive control of THz plasmon propagation in a one-dimensional electronic waveguide
We demonstrate active control over the propagation speed of an electron wavepacket with a temporal duration as short as 4 ps in a quasi-one-dimensional electron waveguide with a length ranging from 10 m to 40 m.
PreprintLoss-Tolerant Quantum Position Verification for Metropolitan Area Networks
Here, we introduce and experimentally demonstrate a loss-tolerant QPV (LT-QPV) protocol whose security is independent of channel loss.
PreprintBold claims, read criticallyReal-world use100 million photons per second from a single organic molecule
The device reaches a collection efficiency of 97% and delivers 100 million photons per second into the first lens.
PreprintAn information-theoretic proof of the Planckian bound for thermalization
We formulate thermalization as a process that prepares states close to the corresponding thermal ensemble for a set of distinct Hamiltonians, and show that quantum mechanics imposes a universal lower bound τ ≥ τ Pl /2 on the thermalization time τ at finite temperature.
Peer-reviewed journalClaims a big stepQuantum many-body mixed phase space revealed by hybrid feedback control
The stabilized trajectories reveal signatures of a quantum many-body mixed phase space emerging from nonlinear variational dynamics, without a direct analogue in few-body quantum systems described by a small number of effective degrees of freedom.
Peer-reviewed journalClaims a big stepSecure Quantum Metasurfaces for Direct Quantum Key Distribution Measurements
Here, we make the metasurface function as the QKD measurement device itself.
PreprintReal-world useVersatile Quantum Machine Learning with an Ultra-low Power Photonic Quantum Reservoir Computer
Here we demonstrate an integrated photonic quantum reservoir computer that achieves nonlinear mapping, fading memory, and task versatility without active tuning of the reservoir core.
PreprintBold claims, read criticallyReal-world useA low-temperature entropy source for on-chip true random number generation: universal robustness beyond device quality
We demonstrate a counterintuitive finding: a single current-biased Josephson junction, regardless of its parameter quality, can serve as a cryptographic-grade true random number generator.
PreprintBold claims, read criticallyReal-world useUniversal scaling laws for correlated decay of many-body quantum systems
Here we exploit this correspondence to establish rigorous and general upper and lower bounds on the maximal decay rate.
Peer-reviewed journalGradient-estimator design overcomes trainability barriers in neural-network-based variational optimization
Here we derive an unbiased direct gradient estimator and introduce the adaptive minimum-variance phase (AMVP) estimator for neural-network variational optimization.
PreprintBold claims, read criticallyClaims a big stepBroadband Quantum Optical Storage with Chemically Engineered Molecular Eu Complex
Using the memory protocol and material, we experimentally demonstrate a quantum optical storage efficiency of 14.9% and a memory bandwidth of 200MHz, which can easily be extended to a few GHz.
PreprintBold claims, read criticallyClaims a big stepQuantum score matching with applications to learning thermal states
In this work, we bridge this gap by establishing a general quantum score-matching framework with end-to-end theoretical guarantees.
PreprintCode availableA Coherent Memory Register for Sequential Quantum Generative Modeling, with Application to Calorimeter Showers
We remove both constraints for this problem, using a construction drawn from the sequential-generation and hidden-quantum-Markov-model literature.
PreprintSyndrome measurements enable deterministic fault-tolerant gates
Two Pauli rotations, followed by syndrome measurement and Clifford feed-forward, then implement a deterministic logical gate on every stabilizer code of distance at least two, in a suitable logical basis.
PreprintClaims a big stepFundamental Physics at the Frontier of Noisy Quantum Computation
This thesis presents several advancements in the use of quantum simulation and quantum information to probe fundamental physics.
PreprintIntrinsic Vectorial Gradiometry via Quantum Control of a Spin-based Sensor
To overcome these limitations, we introduce a quantum control sequence that enables intrinsic temporal and spatial vectorial gradiometry of magnetic fields using a single quantum sensor.
PreprintReal-world useRobust many-body quantum batteries
Here we devise a universal low-complexity protocol that steers any initial state towards exactly one scar---representing a charged state of the battery---from which a macroscopic amount of work can be extracted using local unitary operations.
PreprintBold claims, read criticallyClaims a big stepHybrid quantum-classical attention for histopathology-based molecular profiling in data-limited cancers
We developed a hybrid quantum-classical strategy that replaces softmax attention in a transformer for histopathology-based gene expression prediction with a quantum-derived doubly stochastic matrix (QDSM).
PreprintReal-world useI Prove, Therefore I Am: Spatiotemporal Multi-Party Computation
We provide constructions achieving this new MPC notion.
PreprintClaims a big stepEmergent Prethermal Symmetries for Scalable Hamiltonian Learning
On a -dimensional lattice of qubits, this enables learning every coefficient to accuracy , with failure probability at most , using total evolution time Thus, our learning protocol attains the information-theoretically optimal \(1/\varepsilon\) dependence up to polylogarithmic factors using product-state preparation, single-qubit measurements, and non-adaptive experiments.
PreprintDoes Not Relativize
We construct an oracle relative to which , resolving a long-standing open question in quantum complexity theory.
PreprintClaims a big stepMagnetic graphs for cavity quantum electrodynamics
Here we propose a magnetic graph model for single-atom cavity QED that offers a unified description of quantum dynamics from the weak- to the ultrastrong-coupling regime via graph connectivity.
Peer-reviewed journalObservation of Universal Quantum Chaos at Shallow Depths
Here we show, theoretically and experimentally, that universality emerges already at shallow depths in chaotic quantum circuits.
PreprintFully passive monolithic silicon quantum photonic circuit for entangled photon-pair generation
Here, we demonstrate a fully integrated silicon quantum photon-pair source operating without active tuning of any component.
PreprintComplementarity Test with Unmeasured, Permanently Inaccessible Path Markers
We address this loophole using a quantum eraser that isolates the encoding of path information in the joint quantum state from its later measurement and causal accessibility.
PreprintWhen are bosonic Gaussian states classical to learn?
Our results tightly characterize a quantum-to-classical crossover in the learnability of bosonic Gaussian states, reveal a novel connection between fundamental physics and statistical learning theory, and have implications for real-world sensing experiments.
PreprintSustained growth of quantum circuit complexity in many-body Hamiltonian dynamics
We unconditionally prove that for generic local Hamiltonians and typical initial product states at high effective temperature, the robust quantum circuit complexity must grow over a very long period of time, attaining an exponentially large value at late times.
PreprintEfficient learning of Clifford disentanglers and typical -doped unitaries with exponentially more gates
We give efficient algorithms for testing and recovering hidden tensor-product structure in unknown pure state vectors of the form , where is an arbitrary unknown Clifford unitary.
PreprintNon-Abelian sheaf quantum LDPC codes: good and magical
In this work, we develop a general framework for constructing non-Abelian quantum low-density parity-check (qLDPC) codes by gauging sheaf codes via cup products and use it to obtain families with constant encoding rate and linear distance.
PreprintParameter-Decoupled Quantum Superresolution without Multiparameter Estimation
Here we introduce a parameter-decoupled measurement that determines the separation of realistic passive sources without estimating their unknown brightness imbalance, mutual coherence, or relative phase.
PreprintSoft decoding for quantum LDPC codes with experimental validation
We introduce a soft beam search decoder for quantum low-density parity-check codes that uses internal decoder data as a confidence metric, removing the need for extra computation.
PreprintOptimising Cryogenic Wiring for Microwave-frequency Millikelvin Quantum Processors
We identify optimised configurations that substantively outperform conventional designs in device temperature, noise burden, qubit capacity and other practical metrics.
PreprintReal-world useA Proof of Shor's Orthogonal-Measurement Conjecture and the Structure of Information-Optimal Quantum Measurements
For faithful ensembles, an affine information bound is exact precisely when this algebra is commutative; its joint spectral measurement is then optimal, and every optimal finite POVM refines it.
PreprintCode availableAll you need is the universal correlation detector: A unified approach to universalize communication protocols over quantum channels
These results turn universal correlation detection into a systematic tool for universal protocol design, providing a unified route to designing capacity-achieving protocols for many communication tasks over unknown quantum channels.
PreprintA quantum lower bound for path finding in welded trees
We prove that this is inherent: any quantum algorithm needs exponentially many queries to find a path between the roots of an independently matched welded tree graph.
PreprintCritical Touching of Temporal Entanglement Transitions
In a periodically driven transverse - Ising chain, we show that two such TETs can merge into a critical touching, where the leading levels meet tangentially without exchanging, realizing the temporal analog of a continuous phase transition.
PreprintFlow-Based Lattice Surgery Optimization with Runtime T Gate Scheduling
We present FlowRouter, the first topological lattice surgery compiler that places Clifford routing and stochastic magic state cultivation inside a single 3D embedding.
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