Adaptive Self-Optimization cuts NV thermometer heating 44% using PAS-Q reinforcement learning. The method also yields a 33% increase in spin polarization rate and a 71% reduction in optimization time.
Key points
44% reduction in laser-induced heating.
33% increase in spin polarization rate based on T1 relaxation analysis.
Sources
Hybrid Quantum--Classical Pauli-Correlator Architecture for Image Reconstruction announced
Hybrid Quantum--Classical Pauli-Correlator Architecture for Image Reconstruction introduces the Pauli-Correlator Autoencoder that rebuilds images with peak signal-to-noise ratios between 25.8 and 41.6 dB on six public datasets. The model uses six qubits arranged either linearly (PCAE1D) or on a grid (PCAE2D) and runs on current IBM quantum computers.
Key points
Image patches are compressed as matrix product states and processed by a small quantum circuit before reconstruction by a classical neural network.
Five trained models executed on real IBM hardware achieve reconstruction quality between 25.90 and 31.52 dB.
Sources
Broken-Symmetry Reference States for SQD reach near-DMRG
Broken-Symmetry Reference States for Sample-Based Quantum Diagonalization (SQD) use a BS-UHF starting point and obtain an energy of –327.235076 Ha for the Fe₄S₄ cubane, within 4.3 mHa of the finite-D = 4000 DMRG result. The workflow extension lowers the mean-field reference by ≈534 mHa relative to RHF and demonstrates that reference-state preparation drives SQD accuracy under strong correlation.
Key points
BS-UHF reference energy: –327.0809 Ha versus RHF –326.5474 Ha (≈534 mHa lower)
SQD energy result: –327.235076 Ha, 4.3 mHa above DMRG (–327.2393952 Ha) and ~512-517 mHa below previous RHF-SQD calculation
Sources
Long-lived quantum memories with rare-earth ions doped in crystals
Long-lived quantum memories with rare-earth ions doped in crystals reviews spin coherence times up to hours, light storage up to minutes-to-hours, and single-photon quantum storage up to minutes. The paper outlines zero-first-order-Zeeman transitions and dynamical decoupling as key mechanisms. It also lists remaining challenges and future prospects for quantum networks.
Key points
Spin coherence time achieved on the order of hours in rare-earth-doped crystals
Light storage time demonstrated from minutes to hours, and quantum storage time at the single-photon level reaching minutes
Sources
Motional Decoherence of an atom internal state – relativistic treatment
Motional Decoherence of the internal state of an atom by vacuum and thermal fluctuations of a quantum field presents a fully relativistic calculation of internal dynamics. It shows significant discrepancies with non-relativistic approaches even at low atomic speeds and recommends deriving equations in a covariant framework before taking low-velocity limits.
Key points
Fully relativistic calculation based on covariance principles.
Non-relativistic treatment yields significant discrepancies at low speeds.
Sources
Decoy-state quantum key distribution with a leaky Mach-Zehnder receiver
Decoy-state quantum key distribution with a leaky Mach-Zehnder receiver presents a security proof for phase-encoded BB84 using imbalanced beam splitters and two threshold detectors that leak fine-grained detection patterns. The proof derives a lower bound on Bob’s single-photon contributions and applies a phase-error framework that makes the leakage-induced correction to the phase-error rate independent of channel loss.
Key points
Security proof for phase-encoded decoy-state BB84 with a Mach-Zehnder receiver that has imbalanced beam splitters and leaky detectors.
Leakage-induced correction to the phase-error rate is independent of channel loss, enabling loss-tolerant security despite receiver leakage.
Sources
On the Hardness of Approximate Quantum Circuit Membership and Optimization
On the Hardness of Approximate Quantum Circuit Membership and Optimization proves PP-hardness of approximate membership for promise-free inputs across several gate sets and distance metrics. It shows PP-hardness for all non-trivial ε when S = {I} and the metric is trace-based, even for classical-reversible gate-sets. The results also imply PP-hardness of circuit optimization when minimizing total, non-Clifford, or superposition gate depth or count.
Key points
Approximate membership is PP-hard for wide ranges of ε when the circuit gate-set can implement Clifford+T.
PP-hardness holds for all non-trivial ε if S = {I} or S contains only generalized permutation matrices, I ∈ S, and the metric is trace-based.
Sources
Approximate Synthetic Spectra of Quantum Systems Associated with Compact Lie Groups
Approximate Synthetic Spectra of Quantum Systems Associated with Compact Lie Groups is a new arXiv preprint that studies synthetic spectra of position-momentum and angular-momentum systems. It shows the position-momentum spectrum fills the plane for sufficiently small ℏ and the angular-momentum spectrum can contain any prescribed ball. It also proves highest-weight coadjoint orbits lie in regional synthetic spectra under an explicit variance bound, with examples for SU(n), SO(n) and Sp(n).
Key points
Position-momentum synthetic spectrum fills the plane when ℏ is sufficiently small.
Angular-momentum synthetic spectrum contains any prescribed ball and includes highest-weight coadjoint orbits under an explicit variance bound.
