Quantum Journal

Quantum Inversion of Units in Group Rings: Block Dimension, Not Commutativity, Governs Hardness

Several public-key schemes base their security on the belief that inverting a unit of a group ring is hard. A recent result showed that this belief is false on a quantum computer when the group is abelian. To restore security, designers moved to non-abelian groups, especially dihedral groups, believing that the hardness of the dihedral hidden subgroup problem (HSP) would protect the scheme. This paper shows that unit inversion is a different pro...

Conditional-squeezing gate in superconducting circuits

We present an implementation of a conditional-squeezing gate that squeezes a SQUID-terminated resonator mode along a direction determined by the state of a dispersively coupled qubit. This gate generalizes the controlled-squeezing gate [Phys. Rev. A \textbf{111}, 042606 (2025)], and relies on a refocusing technique to suppress unwanted effects arising from slowly varying time-dependent terms in the Hamiltonian during the state-dependent parametr...

Digital quantum simulations of scattering in quantum field theories using W states

Xanadu and AMD Launch Open-Source Backline Extension for PennyLane

Xanadu and AMD have launched Backline, an open-source framework integrated into Xanadu's PennyLane platform, to connect quantum and classical hardware. It provides ultra-low-latency links across CPUs, GPUs, FPGAs, and SmartNICs, resolving the classical-quantum data bottleneck for applications like quantum error correction. Backline enables Python-native, microsecond-scale communication, allowing standard processors to handle real-time quantum feedback loops and offering a hardware-agnostic ar...