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Random unitaries are a central object of study in quantum information, with applications to quantum computation, quantum many-body physics, and quantum cryptography. Recent work has constructed unitary designs and pseudorandom unitaries…

Quantum Physics · Physics 2025-09-29 Ben Foxman , Natalie Parham , Francisca Vasconcelos , Henry Yuen

Quantum computing offers advantages over classical computation, yet the precise features that set the two apart remain unclear. In the standard quantum circuit model, adding a 1-qubit basis-changing gate -- commonly chosen to be the…

Quantum Physics · Physics 2025-11-26 Wang Fang , Chris Heunen , Robin Kaarsgaard

In Quantum Machine Learning (QML) and Quantum Finance, amplitude encoding is often motivated by its logarithmic storage capacity arXiv:1307.0411. This paradigm typically relies on the mapping $\psi = \sqrt{P}$, treating the quantum state as…

Quantum Physics · Physics 2026-02-26 Sebastian Zając , Jacob L. Cybulski , Bartosz Dziewit , Tomasz Kulpa

Quantum fingerprinting is a technique that maps classical input word to a quantum state. The obtained quantum state is much shorter than the original word, and its processing uses less resources, making it useful in quantum algorithms,…

Quantum Physics · Physics 2023-09-07 Mansur Ziiatdinov , Aliya Khadieva , Abuzer Yakaryılmaz

Quantum neuromorphic computing (QNC) is a sub-field of quantum machine learning (QML) that capitalizes on inherent system dynamics. As a result, QNC can run on contemporary, noisy quantum hardware and is poised to realize challenging…

Quantum Physics · Physics 2024-02-22 Rodrigo Araiza Bravo , Khadijeh Najafi , Taylor L. Patti , Xun Gao , Susanne F. Yelin

The increasing depth of quantum circuits presents a major limitation for the execution of quantum algorithms, as the limited coherence time of physical qubits leads to noise that manifests as errors during computation. In this work, we…

Quantum Physics · Physics 2026-03-24 Spyros Tserkis , Muhammad Umer , Dimitris G. Angelakis

Low-depth random circuit codes possess many desirable properties for quantum error correction but have so far only been analyzed in the code capacity setting where it is assumed that encoding gates and syndrome measurements are noiseless.…

Quantum Physics · Physics 2023-12-01 Jon Nelson , Gregory Bentsen , Steven T. Flammia , Michael J. Gullans

Usual scenarios of fault-tolerant computation are concerned with the fault-tolerant realization of quantum algorithms that compute classical functions, such as Shor's algorithm for factoring. In particular, this means that input and output…

Quantum Physics · Physics 2025-12-03 Matthias Christandl , Omar Fawzi , Ashutosh Goswami

Quantum computers will require encoding of quantum information to protect them from noise. Fault-tolerant quantum computing architectures illustrate how this might be done but have not yet shown a conclusive practical advantage. Here we…

Quantum Physics · Physics 2019-03-01 Robin Harper , Steven T. Flammia

Controlled-NOT (CNOT) gates are commonly included in the standard gate set of quantum processors and provide an important way to entangle qubits. For fixed-frequency qubits using the cross-resonance entangling technique, using the…

Quantum Physics · Physics 2020-09-04 Travis Hurant , Daniel D. Stancil

Quantum network coding is an effective solution for alleviating bottlenecks in quantum networks. We introduce a measurement-based quantum network coding scheme for quantum repeater networks (MQNC), and analyze its behavior based on results…

Quantum Physics · Physics 2018-07-04 Takaaki Matsuo , Takahiko Satoh , Shota Nagayama , Rodney Van Meter

A Hadamard-free Clifford transformation is a circuit composed of quantum Phase (P), CZ, and CNOT gates. It is known that such a circuit can be written as a three-stage computation, -P-CZ-CNOT-, where each stage consists only of gates of the…

Quantum Physics · Physics 2023-10-18 Dmitri Maslov , Willers Yang

Quantum error correction (QEC) is indispensable for scalable quantum computing, but implementing it with minimal hardware overhead remains a central challenge. Large spin systems with collective degrees of freedom offer a promising route to…

Quantum Physics · Physics 2026-03-18 Charlotte Franke , Dorian A. Gangloff

Quantum programs today are written at a low level of abstraction - quantum circuits akin to assembly languages - and the unitary parts of even advanced quantum programming languages essentially function as circuit description languages.…

Programming Languages · Computer Science 2025-12-02 Chris Heunen , Louis Lemonnier , Christopher McNally , Alex Rice

In this paper, we extend the techniques used in our previous work to show that there exists a probabilistic Turing machine running within time $O(n^k)$ for all $k\in\mathbb{N}_1$ accepting a language $L_d$ that is different from any…

Computational Complexity · Computer Science 2026-05-26 Tianrong Lin

We consider experimentally feasible chains of trapped ions with pseudo-spin 1/2, and find models that can potentially be used to implement error-resistant quantum computation. Similar in spirit to classical neural networks, the…

Quantum Physics · Physics 2009-10-20 Sibylle Braungardt , Aditi Sen De , Ujjwal Sen , Maciej Lewenstein

We address the problems of constructing quantum convolutional codes (QCCs) and of encoding them. The first construction is a CSS-type construction which allows us to find QCCs of rate 2/4. The second construction yields a quantum…

Quantum Physics · Physics 2009-05-24 Markus Grassl , Martin Roetteler

In a sequence of seminal results in the 80's, Kaltofen showed that the complexity class VP is closed under taking factors. A natural question in this context is to understand if other natural classes of multivariate polynomials, for…

Computational Complexity · Computer Science 2018-03-19 Chi-Ning Chou , Mrinal Kumar , Noam Solomon

We prove that for any additive noise channel over $\mathbb{F}_q$, there exist error-correcting codes approaching channel capacity encodable by arithmetic circuits (with weighted addition gates) over $\mathbb{F}_q$ of size $O(n)$ and depth…

Information Theory · Computer Science 2026-04-21 Yuan Li

We present a protocol to encode and decode arbitrary quantum states in the parity architecture with constant circuit depth using measurements, local nearest-neighbor and single-qubit operations only. While this procedure typically requires…

Quantum Physics · Physics 2024-04-17 Anette Messinger , Michael Fellner , Wolfgang Lechner