Gunhee Cho • Published: 2026-01-14
This book gives a geometry-first, hardware-aware route through quantum-information workflows, with one goal: connect states, circuits, and measurement to deterministic classical pipelines that make hybrid quantum systems run. Part 1 develops the backbone (essential linear algebra, the Bloch-sphere viewpoint, differential-geometric intuition, and quantum Fisher information geometry) so evolution ca...
Kyrylo Simonov, Marcello Caleffi, Jessica Illiano, Jacquiline Romero, Angela Sara Cacciapuoti • Published: 2023-11-22
Superposed orders of quantum channels have already been proved - both theoretically and experimentally - to enable unparalleled opportunities in the quantum communication domain. As a matter of fact, superposition of orders can be exploited within the quantum computing domain as well, by relaxing the (traditional) assumption underlying quantum computation about applying gates in a well-defined cau...
Soshun Naito, Yasunari Suzuki, Yuuki Tokunaga • Published: 2026-01-14
In fault-tolerant quantum computing, a large number of physical qubits are required to construct a single logical qubit, and a single quantum node may be able to hold only a small number of logical qubits. In such a case, the idea of distributed fault-tolerant quantum computing (DFTQC) is important to demonstrate large-scale quantum computation using small-scale nodes. However, the design of distr...
Marvin Erdmann, Lukas Karch, Abhishek Awasthi, Caitlin Isobel Jones, Pallavi Bhardwaj, Florian Krellner, Jonas Stein, Claudia Linnhoff-Popien, Nico Kraus, Peter Eder, Sarah Braun, Tong Liu • Published: 2026-01-13
This whitepaper surveys the current landscape and short- to mid-term prospects for quantum-enabled optimization and machine learning use cases in industrial settings. Grounded in the QCHALLenge program, it synthesizes hardware trajectories from different quantum architectures and providers, and assesses their maturity and potential for real-world use cases under a standardized traffic-light evalua...
Viktor Khinevich, Wataru Mizukami • Published: 2026-01-13
We present systematic and resource-efficient constructions of continuous symmetry projectors, particularly $U(1)$ particle number and $SU(2)$ total spin, tailored for fault-tolerant quantum computations. Our approach employs a linear combination of unitaries (LCU) as well as generalized quantum signal processing (GQSP and GQSVT) to implement projectors. These projectors can then be coherently appl...
Giovanni de Felice, Boldizsár Poór, Cole Comfort, Lia Yeh, Mateusz Kupper, William Cashman, Bob Coecke • Published: 2026-01-13
Photonic systems offer a promising platform for interconnecting quantum processors and enabling scalable, networked architectures. Designing and verifying such architectures requires a unified formalism that integrates linear algebraic reasoning with probabilistic and control-flow structures. In this work, we introduce a graphical framework for distributed quantum computing that brings together li...
Kazuhiro Seki, Yuta Kikuchi, Tomoya Hayata, Seiji Yunoki • Published: 2026-01-13
We demonstrate a dissipative protocol for ground-state preparation of a quantum spin chain on a trapped-ion quantum computer. As a first step, we derive a Kraus representation of a dissipation channel for the protocol recently proposed by Ding et al. [Phys. Rev. Res. 6, 033147 (2024)] that still holds for arbitrary temporal discretization steps, extending the analysis beyond the Lindblad dynamics ...
Yu Yang, Igor Kladaric, Martynas Skrabulis, Michael Eichenberger, Stefano Marti, Simon Storz, Jonathan Esche, Raquel Garcia Belles, Max-Emanuel Kern, Andraz Omahen, Arianne Brooks, Marius Bild, Mateo Fadel, Yiwen Chu • Published: 2026-01-12
Hybrid quantum systems combine the unique advantages of different physical platforms with the goal of realizing more powerful and practical quantum information processing devices. Mechanical systems, such as bulk acoustic wave resonators, feature a large number of highly coherent harmonic modes in a compact footprint, which complements the strong nonlinearities and fast operation times of supercon...
Nobumasa Ishida, Yoshihiko Hasegawa • Published: 2026-01-12
Branch selection, including postselection, is a standard method for implementing nonunitary transformations in quantum algorithms. Conventionally, states associated with unsuccessful branches are discarded and treated as useless. Here we propose a generic framework that reuses these failure branches as thermodynamic resources. The central element is an athermal bath that is naturally generated dur...
Siddhant Singh, Rikiya Kashiwagi, Kazufumi Tanji, Wojciech Roga, Daniel Bhatti, Masahiro Takeoka, David Elkouss • Published: 2026-01-12
Fault-tolerant modular quantum computing requires stabilizer measurements across the modules in a quantum network. For this, entangled states of high quality and rate must be distributed. Currently, two main types of entanglement distribution protocols exist, namely emission-based and scattering-based, each with its own advantages and drawbacks. On the one hand, scattering-based protocols with cav...