Papers
Tunable Nonlocal ZZ Interaction for Remote Controlled-Z Gates Between Distributed Fixed-Frequency Qubits
Benzheng Yuan, Chaojie Zhang, Haoran He +9 more·Mar 30, 2026
Fault-tolerant quantum computing requires large-scale superconducting processors, yet monolithic architectures face increasing constraints from wiring density, crosstalk, and fabrication yield. Modular superconducting platforms offer a scalable alter...
Quantum engineering with ultracold polar molecules using trap-induced resonances
Sakthikumaran Ravichandran, Piotr Kulik, Krzysztof Jachymski·Mar 30, 2026
Polar molecules represent a promising platform for quantum simulation and computation protocols. Highly controllable arrays of optical tweezers are now accessible in experiments, allowing for unprecedented control of individual molecules. Motional de...
PyEncode: An Open-Source Library for Structured Quantum State Preparation
Krishnan Suresh, Sanjay Suresh·Mar 30, 2026
Quantum algorithms require encoding classical vectors as quantum states, a step known as amplitude encoding. General-purpose state preparation routines accept any input vector of length $N = 2^m$ and produce circuits with $\bigO{2^m}$ gates. However,...
Exponentially cheaper coherent phase estimation via uncontrolled unitaries
Mirko Amico·Mar 29, 2026
Phase kickback is a fundamental primitive that is used in many quantum algorithms, such as quantum phase estimation. Here we observe that by using information about the controlled unitary, we can replace the controlled unitary with an uncontrolled on...
Digital Predistortion of Optical Fields for Fast and High-Fidelity Entangling Gates in Trapped-Ion Qubits
Jovan Markov, Yotam Shapira, Ayelet Hasson +4 more·Mar 29, 2026
High-fidelity quantum gates require precise classical control signals, yet the analog hardware delivering these signals introduces nonlinear distortions that degrade gate performance. We demonstrate digital predistortion of an acousto-optic modulator...
First order Maxwell operator formalism for macroscopic quantum electrodynamics
Ishita Agarwal, Ankit Kundu, Christian M. Lange +1 more·Mar 29, 2026
Standard macroscopic QED is built on the second-order Green's function for the electric field and discards open-system boundary terms. Here we develop a first-order electromagnetic operator approach that retains both $\mathbf{E}$ and $\mathbf{H}$ and...
Decoherence-Free Qubit and Chiral Emission from a Giant Molecule in Waveguide QED
Yang Wang, Juan José García-Ripoll, Alan C. Santos·Mar 28, 2026
Combining decoherence protection with directional photon emission in a single waveguide quantum electrodynamics (QED) device remains an open challenge. Here we show that an artificial giant molecule -- strongly interacting artificial atoms coupled to...
Single-photon-boosted type-I fusion gates
A. A. Melkozerov, S. S. Straupe, M. Yu. Saygin·Mar 28, 2026
Fusion measurements are a key primitive for linear-optical quantum computing and quantum networks. Type-I and type-II fusion gates are widely used to combine small entangled resource states into larger photonic states, but without ancillary resources...
Ultralow-power coherent qubit control using AQFP logic at millikelvin temperatures
Hiroto Mukai, Akiyoshi Tomonaga, Rui Wang +5 more·Mar 28, 2026
Qubit controllers are essential for scaling superconducting quantum processors, but implementing them at the 10 mK stage of a dilution refrigerator remains challenging due to stringent cooling constraints. Here we report an ultralow-power qubit contr...
Expressibility of neural quantum states: a Walsh-complexity perspective
Taige Wang·Mar 27, 2026
Neural quantum states are powerful variational wavefunctions, but it remains unclear which many-body states can be represented efficiently by modern additive architectures. We introduce Walsh complexity, a basis-dependent measure of how broadly a wav...
Autonomous Hamiltonian certification and changepoint detection
Steven T. Flammia, Dmitrii Khitrin, Muzhou Ma +3 more·Mar 27, 2026
Modern quantum devices require high-precision Hamiltonian dynamics, but environmental noise can cause calibrated Hamiltonian parameters to drift over time, necessitating expensive recalibration. Detecting when recalibration is needed is challenging, ...
Entanglement as Memory: Mechanistic Interpretability of Quantum Language Models
Nathan Roll·Mar 27, 2026
Quantum language models have shown competitive performance on sequential tasks, yet whether trained quantum circuits exploit genuinely quantum resources -- or merely embed classical computation in quantum hardware -- remains unknown. Prior work has e...
Controlled-Z gates with giant atoms in structured waveguides
Walter Rieck, Ariadna Soro, Anton Frisk Kockum +1 more·Mar 27, 2026
Giant atoms are quantum emitters coupled to waveguides at multiple, spatially separated points, enabling interference effects that fundamentally change their light-matter interactions. A notable consequence of the interference is the emergence of dec...
Decomposition of Multi-Qubit Gates for Circuit Cutting
Ryota Tamura, Tomoya Kashimata, Yohei Hamakawa +2 more·Mar 27, 2026
A large-scale quantum circuit can be partitioned into multiple subcircuits through circuit cutting, where each subcircuit is executed multiple times and the expectation value of the original circuit is reconstructed by classical post-processing from ...
Generalizable Verilog Modeling Framework for Synchronous and Asynchronous Superconducting Pulse-Based Logic Gates
Elisabeth Feng, Robert S. Aviles, Peter A. Beerel·Mar 26, 2026
Superconducting Single Flux Quantum (SFQ) logic offers a promising platform for ultra-low-power, high-frequency computing. However, their pulse-based nature poses challenges for scalable modeling, design, and verification using conventional hardware ...
Two-Gate Extensions of Free Axis and Free Quaternion Selection for Sequential Optimization of Parameterized Quantum Circuits
Joona V. Pankkonen·Mar 26, 2026
We propose two-gate extensions of the sequential single-qubit optimizers, Free Axis Selection (Fraxis) and Free Quaternion Selection (FQS), termed Two-Gate Fraxis (TGF) and Two-Gate FQS (TGFQS), respectively. In contrast to Fraxis and FQS, which upda...
Theory of (Co)homological Invariants on Quantum LDPC Codes
Zimu Li, Yuguo Shao, Fuchuan Wei +2 more·Mar 26, 2026
With recent breakthroughs in the construction of good qLDPC codes and nearly good qLTCs, the study of (co)homological invariants of quantum code complexes, which fundamentally underlie their logical operations, has become evidently important. In this...
Clifford synthesis via generalized S and CZ gates
Vadym Kliuchnikov, Marcus P. da Silva·Mar 25, 2026
We show that any $n$-qubit Clifford unitary can be implemented using at most $2n$ multi-qubit joint measurements. All the multi-qubit joint measurements used for implementing the Clifford unitary can be chosen to form at most two sets of independent ...
Phased outcome-complete simulation
Vadym Kliuchnikov, Adam Paetznick, Marcus P. da Silva·Mar 25, 2026
We generalize the polynomial-time outcome-complete simulation algorithm for stabilizer circuits in arXiv:2309.08676 to track global phases exactly, yielding what we call phased outcome-complete simulation. The original algorithm enabled equivalence c...
Flagging the Clifford hierarchy:~Fault-tolerant logical $\fracπ{2^l}$ rotations via measuring circuit gauge operators of non-Cliffords
Shival Dasu, Ben Criger·Mar 25, 2026
We provide a recursively defined sequence of flag circuits which will detect logical errors induced by non-fault-tolerant $R_{\overline{Z}}(\fracπ{2^l})$ gates on CSS codes with a fault distance of two. As applications, we give a family of circuits w...