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Continuous variable quantum cryptography has developed rapidly in recent decades, but how to verify identity in the continuous variable quantum system is still an urgent issue to be solved. To solve this problem, we propose a continuous…

Quantum Physics · Physics 2022-03-17 Xing-Qiang Zhao , Hai Wan , Lv-Zhou Li

The VC-dimension is a well-studied and fundamental complexity measure of a set system (or hypergraph) that is central to many areas of machine learning. We establish several new results on the complexity of computing the VC-dimension. In…

Computational Complexity · Computer Science 2025-10-24 Florent Foucaud , Harmender Gahlawat , Fionn Mc Inerney , Prafullkumar Tale

We present two strategies to enhance the dynamical entanglement transfer from continuous variable (CV) to finite dimensional systems by employing multiple qubits. First, we consider the entanglement transfer to a composite finite…

Quantum Physics · Physics 2007-05-23 A. Serafini , M. Paternostro , M. S. Kim , S. Bose

We study the uniform $2$-dimensional vector multiple knapsack (2VMK) problem, a natural variant of multiple knapsack arising in real-world applications such as virtual machine placement. The input for 2VMK is a set of items, each associated…

Data Structures and Algorithms · Computer Science 2023-07-06 Tomer Cohen , Ariel Kulik , Hadas Shachnai

We present a single-quench protocol that generates unitary $k$-designs with minimal control. A system first evolves under a random Hamiltonian $H_1$; at a switch time $t_s \geq t_{\mathrm{Th}}$ (the Thouless time), it is quenched to an…

Quantum Physics · Physics 2026-03-17 Yi-Neng Zhou , Robin Löwenberg , Julian Sonner

We prove that random quantum circuits on any geometry, including a 1D line, can form approximate unitary designs over $n$ qubits in $\log n$ depth. In a similar manner, we construct pseudorandom unitaries (PRUs) in 1D circuits in…

Quantum Physics · Physics 2025-01-07 Thomas Schuster , Jonas Haferkamp , Hsin-Yuan Huang

Unclonable encryption, introduced by Broadbent and Lord (TQC'20), is an encryption scheme with the following attractive feature: given a ciphertext, an adversary cannot create two ciphertexts both of which decrypt to the same message as the…

Cryptography and Security · Computer Science 2021-09-16 Prabhanjan Ananth , Fatih Kaleoglu

We present designs for scalable quantum computers composed of qubits encoded in aggregates of four or more Majorana zero modes, realized at the ends of topological superconducting wire segments that are assembled into superconducting…

Instantaneous quantum computing is a sub-universal quantum complexity class, whose circuits have proven to be hard to simulate classically in the Discrete-Variable (DV) realm. We extend this proof to the Continuous-Variable (CV) domain by…

Quantum Physics · Physics 2017-02-21 T. Douce , D. Markham , E. Kashefi , E. Diamanti , T. Coudreau , P. Milman , P. van Loock , G. Ferrini

Topological quantum computing promises intrinsic fault tolerance by encoding quantum information in non-Abelian anyons, where quantum gates are implemented via braiding. While braiding operations are robust against local perturbations, a…

Quantum Physics · Physics 2025-08-15 Themba Hodge , Philipp Frey , Stephan Rachel

Recent studies showed the finite-size security of binary-modulation CV-QKD protocols against general attacks. However, they gave poor key-rate scaling against transmission distance. Here, we extend the security proof based on…

Quantum Physics · Physics 2023-08-30 Takaya Matsuura , Shinichiro Yamano , Yui Kuramochi , Toshihiko Sasaki , Masato Koashi

We present an algorithm for building a circuit that approximates single qubit unitaries with precision {\epsilon} using O(log(1/{\epsilon})) Clifford and T gates and employing up to two ancillary qubits. The algorithm for computing our…

Quantum Physics · Physics 2013-05-13 Vadym Kliuchnikov , Dmitri Maslov , Michele Mosca

We develop a method to connect the infinite-dimensional description of optical continuous-variable quantum key distribution (QKD) protocols to a finite-dimensional formulation. The secure key rates of the optical QKD protocols can then be…

Quantum Physics · Physics 2021-05-26 Twesh Upadhyaya , Thomas van Himbeeck , Jie Lin , Norbert Lütkenhaus

We demonstrate that secure quantum key distribution systems based on continuous variables implementations can operate beyond the apparent 3 dB loss limit that is implied by the beam splitting attack . The loss limit was established for…

Quantum Physics · Physics 2009-11-07 Ch. Silberhorn , T. C. Ralph , N. Lütkenhaus , G. Leuchs

Quantum pseudorandomness, also known as unitary designs, comprise a powerful resource for quantum computation and quantum engineering. While it is known in theory that pseudorandom unitary operators can be constructed efficiently, realizing…

Quantum Physics · Physics 2019-07-24 Jun Li , Zhihuang Luo , Tao Xin , Hengyan Wang , David Kribs , Dawei Lu , Bei Zeng , Raymond Laflamme

This paper investigates the design of low-complexity error correction codes for the verification step in continuous variable quantum key distribution (CVQKD) systems. We design new coding schemes based on quasi-cyclic repeat-accumulate…

Information Theory · Computer Science 2015-10-14 Sarah J. Johnson , Vikram A. Chandrasetty , Andrew M. Lance

Uncloneable encryption is a cryptographic primitive which encrypts a classical message into a quantum ciphertext, such that two quantum adversaries are limited in their capacity of being able to simultaneously decrypt, given the key and…

Quantum Physics · Physics 2024-10-31 Pierre Botteron , Anne Broadbent , Eric Culf , Ion Nechita , Clément Pellegrini , Denis Rochette

Most quantum key distribution (QKD) protocols can be classified as either a discrete-variable (DV) protocol or continuous-variable (CV) protocol, based on how classical information is being encoded. We propose a protocol that combines the…

The impossibility of creating perfect identical copies of unknown quantum systems is a fundamental concept in quantum theory and one of the main non-classical properties of quantum information. This limitation imposed by quantum mechanics,…

Quantum Physics · Physics 2022-11-01 Mina Doosti

We consider the quantum processor based on a chain of trapped ions to propose an architecture wherein the motional degrees of freedom of trapped ions (position and momentum) could be exploited as the computational Hilbert space. We adopt a…