Quantum

Paper

PAC-learning of free-fermionic states is NP-hard

Lennart Bittel, Antonio A. Mele, Jens Eisert, and Lorenzo Leone,

Quantum 9, 1665 (2025).

Free-fermionic states, also known as matchgates or Gaussian states, are a fundamental class of quantum states due to their efficient classical simulability and their crucial role across vari…

Paper

What exactly does Bekenstein bound?

Patrick Hayden and Jinzhao Wang,

Quantum 9, 1664 (2025).

The Bekenstein bound posits a maximum entropy for matter with finite energy confined to a spatial region. It is often interpreted as a fundamental limit on the information that can be stored…

Paper

Prog-QAOA: Framework for resource-efficient quantum optimization through classical programs

Bence Bakó, Adam Glos, Özlem Salehi, and Zoltán Zimborás,

Quantum 9, 1663 (2025).

Current state-of-the-art quantum optimization algorithms require representing the original problem as a binary optimization problem, which is then converted into an equivalent cost Hamiltoni…

Paper

Trade-off relations between measurement dependence and hidden information for factorizable hidden variable models

Ryo Takakura, Kei Morisue, Issei Watanabe, and Gen Kimura,

Quantum 9, 1662 (2025).

The Bell theorem is explored in terms of a trade-off relation between underlying assumptions within the hidden variable model framework. In this paper, recognizing the incorporation of hidde…

Paper

Platonic dynamical decoupling sequences for interacting spin systems

Colin Read, Eduardo Serrano-Ensástiga, and John Martin,

Quantum 9, 1661 (2025).

In the NISQ era, where quantum information processing is hindered by the decoherence and dissipation of elementary quantum systems, developing new protocols to extend the lifetime of quantum…

Paper

Quantum reinforcement learning in continuous action space

Shaojun Wu, Shan Jin, Dingding Wen, Donghong Han, and Xiaoting Wang,

Quantum 9, 1660 (2025).

Quantum reinforcement learning (QRL) is a promising paradigm for near-term quantum devices. While existing QRL methods have shown success in discrete action spaces, extending these technique…

Paper

Optimizing Gate Decomposition for High-Level Quantum Programming

Evandro C. R. Rosa, Eduardo I. Duzzioni, and Rafael de Santiago,

Quantum 9, 1659 (2025).

This paper presents novel methods for optimizing multi-controlled quantum gates, which naturally arise in high-level quantum programming. Our primary approach involves rewriting $U(2)$ gates a…

Paper

Approximation and Generalization Capacities of Parametrized Quantum Circuits for Functions in Sobolev Spaces

Alberto Manzano, David Dechant, Jordi Tura, and Vedran Dunjko,

Quantum 9, 1658 (2025).

Parametrized quantum circuits (PQC) are quantum circuits which consist of both fixed and parametrized gates. In recent approaches to quantum machine learning (QML), PQCs are essentially ubiq…

Paper

Quantum key distribution rates from non-symmetric conic optimization

Andrés González Lorente, Pablo V. Parellada, Miguel Castillo-Celeita, and Mateus Araújo,

Quantum 9, 1657 (2025).

Computing key rates in quantum key distribution (QKD) numerically is essential to unlock more powerful protocols, that use more sophisticated measurement bases or quantum systems of higher d…

Paper

Ultrastrong coupling, nonselective measurement and quantum Zeno dynamics

Stefano Marcantoni and Marco Merkli,

Quantum 9, 1656 (2025).

We study the dynamics of an open quantum system linearly coupled to a bosonic reservoir. We show that, in the ultrastrong coupling limit, the system undergoes a nonselective measurement and…

Paper

Quantum memory assisted observable estimation

Liubov A. Markovich, Attaallah Almasi, Sina Zeytinoğlu, and Johannes Borregaard,

Quantum 9, 1655 (2025).

The estimation of many-qubit observables is an essential task of quantum information processing. The generally applicable approach is to decompose the observables into weighted sums of multi…

Paper

Seedless extractors for device-independent quantum cryptography

Cameron Foreman and Lluis Masanes,

Quantum 9, 1654 (2025).

Device-independent (DI) quantum cryptography aims at providing secure cryptography with minimal trust in, or characterisation of, the underlying quantum devices. A key step in DI protocols i…

Paper

Chaos and magic in the dissipative quantum kicked top

Gianluca Passarelli, Procolo Lucignano, Davide Rossini, and Angelo Russomanno,

Quantum 9, 1653 (2025).

We consider an infinite-range interacting quantum spin-1/2 model, undergoing periodic kicking and dissipatively coupled with an environment. In the thermodynamic limit, it is described by cl…

Paper

Device independent security of quantum key distribution from monogamy-of-entanglement games

Enrique Cervero-Martín and Marco Tomamichel,

Quantum 9, 1652 (2025).

We analyse two party non-local games whose predicate requires Alice and Bob to generate matching bits, and their three party extensions where a third player receives all inputs and is requir…

Paper

Spectral chaos bounds from scaling theory of maximally efficient quantum-dynamical scrambling

Tara Kalsi, Alessandro Romito, and Henning Schomerus,

Quantum 9, 1651 (2025).

A key conjecture about the evolution of complex quantum systems towards an ergodic steady state, known as scrambling, is that this process acquires universal features when it is most efficie…

Paper

Quantum reversal: a general theory of coherent quantum absorbers

Mankei Tsang,

Quantum 9, 1650 (2025).

The fascinating concept of coherent quantum absorber – which can absorb any photon emitted by another system while maintaining entanglement with that system – has found diverse implications…

Category: Paper