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In this work, we report on a novel quantum gate approximation algorithm based on the application of parametric two-qubit gates in the synthesis process. The utilization of these parametric two-qubit gates in the circuit design allows us to…

Quantum Physics · Physics 2022-11-16 Péter Rakyta , Zoltán Zimborás

We present a method to construct infinite families of entangling $2$-qudit gates, and amongst them entangling $2$-qudit gates which satisfy the Yang-Baxter equation. We show that, given $2$-qudit gates $c$ and $d$, if $c$ or $d$ is…

Group Theory · Mathematics 2024-11-20 Fabienne Chouraqui

The capacity of a quantum gate to produce entangled states on a bipartite system is quantified in terms of the entangling power. This quantity is defined as the average of the linear entropy of entanglement of the states produced after…

Quantum Physics · Physics 2022-01-05 D. Morachis , Jesús A. Maytorena

The creation complexity of a quantum state is the minimum number of elementary gates required to create it from a basic initial state. The creation complexity of quantum states is closely related to the complexity of quantum circuits, which…

Quantum Physics · Physics 2022-02-11 Zixuan Hu , Sabre Kais

Quantum computing is currently limited by the cost of two-qubit entangling operations. In order to scale up quantum processors and achieve a quantum advantage, it is crucial to economize on the power requirement of two-qubit gates, make…

Notions of circuit complexity and cost play a key role in quantum computing and simulation where they capture the (weighted) minimal number of gates that is required to implement a unitary. Similar notions also become increasingly prominent…

Quantum Physics · Physics 2021-07-13 J. Eisert

While there is a general consensus about the structure of one qubit operations in topological quantum computer, two qubits are as usual a more difficult and complex story of different attempts with varying approaches, problems and…

Quantum Physics · Physics 2025-09-15 Sergey Mironov , Andrey Morozov

We present two sets of computable entanglement measures for multipartite systems where each subsystem can have different degrees of freedom (so-called qudits). One set, called 'separability' measure, reveals which of the subsystems are…

Quantum Physics · Physics 2009-06-10 Beatrix C. Hiesmayr , Marcus Huber , Philipp Krammer

Adaptive quantum circuits, leveraging measurements and classical feedback, significantly expand the landscape of realizable quantum states compared to their non-adaptive counterparts, enabling the preparation of long-range entangled states…

Quantum Physics · Physics 2025-09-23 Guoding Liu , Junjie Chen , Xiongfeng Ma

Multipartite entanglement is an essential aspect of quantum systems, needed to execute quantum algorithms, implement error correction, and achieve quantum-enhanced sensing. In solid-state quantum registers such nitrogen-vacancy (NV) centers…

Quantum Physics · Physics 2026-02-24 Joseph D. Minnella , Mathieu Ouellet , Amelia R. Klein , Lee C. Bassett

Quantum circuits of a general quantum gate acting on multiple $d$-level quantum systems play a prominent role in multi-valued quantum computation. We first propose a new recursive Cartan decomposition of semi-simple unitary Lie group…

Quantum Physics · Physics 2024-05-29 Gui-Long Jiang , Wen-Qiang Liu , Hai-Rui Wei

Quantum circuit complexity quantifies the minimal number of gates needed to realize a unitary transformation and plays a central role in quantum computation. In this work, we investigate the complexity of quantum circuits through coherence…

Quantum Physics · Physics 2026-04-08 Linlin Ye , Zhaoqi Wu , Nanrun Zhou

We analyze the complexity of synthesizing random states and unitary operators in a multi-qudit system in two paradigms. In one case, we consider the situation in which we manipulate the system by applying a sequence of one- and two-qudit…

Quantum Physics · Physics 2026-05-11 Sahel Ashhab , Bora Basyildiz

We consider the Unitary Permutation problem which consists, given $n$ unitary gates $U_1, \ldots, U_n$ and a permutation $\sigma$ of $\{1,\ldots, n\}$, in applying the unitary gates in the order specified by $\sigma$, i.e. in performing…

Quantum Physics · Physics 2016-10-11 Stefano Facchini , Simon Perdrix

We show that any pseudoentangled state ensemble with a gap of $t$ bits of entropy requires $\Omega(t)$ non-Clifford gates to prepare. This bound is tight up to polylogarithmic factors if linear-time quantum-secure pseudorandom functions…

Quantum Physics · Physics 2026-03-23 Sabee Grewal , Vishnu Iyer , William Kretschmer , Daniel Liang

Developing quantum computers for real-world applications requires understanding theoretical sources of quantum advantage and applying those insights to design more powerful machines. Toward that end, we introduce a high-fidelity gate set…

Quantum Physics · Physics 2021-08-04 Alexander D. Hill , Mark J. Hodson , Nicolas Didier , Matthew J. Reagor

Quantifying quantum states' complexity is a key problem in various subfields of science, from quantum computing to black-hole physics. We prove a prominent conjecture by Brown and Susskind about how random quantum circuits' complexity…

We investigate notions of complexity of states in continuous quantum-many body systems. We focus on Gaussian states which include ground states of free quantum field theories and their approximations encountered in the context of the…

High Energy Physics - Theory · Physics 2018-11-15 Shira Chapman , Michal P. Heller , Hugo Marrochio , Fernando Pastawski

Physical systems representing qubits typically have one or more accessible quantum states in addition to the two states that encode the qubit. We demonstrate that active involvement of such auxiliary states can be beneficial in constructing…

Quantum Physics · Physics 2014-04-04 Dmitry Solenov , Sophia E. Economou , Thomas L. Reinecke

The quantum marginal problem consists in deciding whether a given set of marginal reductions is compatible with the existence of a global quantum state or not. In this work, we formulate the problem from the perspective of dynamical systems…

Quantum Physics · Physics 2022-09-29 Daniel Uzcátegui Contreras , Dardo Goyeneche