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Quantum circuit mapping is a crucial process in the quantum circuit compilation pipeline, facilitating the transformation of a logical quantum circuit into a list of instructions directly executable on a target quantum system. Recent…

Quantum Physics · Physics 2024-12-10 Di Yu , Kun Fang

Quantum circuits consisting of Clifford and matchgates are two classes of circuits that are known to be efficiently simulatable on a classical computer. We introduce a unified framework that shows in a transparent way the special structure…

Quantum Physics · Physics 2024-05-24 Igor Ermakov , Oleg Lychkovskiy , Tim Byrnes

Quantum signal processing is a framework for implementing polynomial functions on quantum computers. To implement a given polynomial $P$, one must first construct a corresponding complementary polynomial $Q$. Existing approaches to this…

Quantum Physics · Physics 2025-06-16 Bjorn K. Berntson , Christoph Sünderhauf

To implement any quantum operation (a.k.a. ``superoperator'' or ``CP map'') on a d-dimensional quantum system, it is enough to apply a suitable overall unitary transformation to the system and a d^2-dimensional environment which is…

Quantum Physics · Physics 2015-06-26 Christof Zalka , Eleanor Rieffel

Current monolithic quantum computer architectures have limited scalability. One promising approach for scaling them up is to use a modular or multi-core architecture, in which different quantum processors (cores) are connected via quantum…

Sequences of commuting quantum operators can be parallelized using entanglement. This transformation is behind some optimal quantum metrology protocols and recent results on quantum circuit complexity. We show that dephasing quantum maps in…

Quantum Physics · Physics 2012-05-29 Sergio Boixo , Chris Heunen

Quantum entanglement is an important phenomenon in quantum information theory. To detect entanglement theoretically, positive but not completely positive maps are used. The Kadison-Schwarz (KS) inequality interpolates between positivity and…

Quantum Physics · Physics 2025-09-23 Hajir Al Zadjali , Farrukh Mukhamedov

Identification of possible transformations of quantum objects including quantum states and quantum operations is indispensable in developing quantum algorithms. Universal transformations, defined as input-independent transformations, appear…

Quantum Physics · Physics 2025-05-27 Satoshi Yoshida , Akihito Soeda , Mio Murao

We prove that all injective maps on positive complex matrices which preserve order and shrink spectrum are implemented by unitary or antiunitary conjugations. We show by counterexamples that all assumptions are indispensable. The result…

Functional Analysis · Mathematics 2022-04-26 Mateo Tomašević

Concurrent remote entanglement of distant, non-interacting quantum entities is a crucial function for quantum information processing. In contrast with the existing protocols which employ addition of signals to generate entanglement between…

Quantum Physics · Physics 2017-12-11 Ananda Roy , Liang Jiang , A. Douglas Stone , Michel Devoret

A quantum processor is a device with a data register and a program register. The input to the program register determines the operation, which is a completely positive linear map, that will be performed on the state in the data register. We…

Quantum Physics · Physics 2009-11-07 Mark Hillery , Mario Ziman , Vladimir Buzek

Quantum compilation is the process of converting a target unitary operation into a trainable unitary represented by a quantum circuit. It has a wide range of applications, including gate optimization, quantum-assisted compiling, quantum…

Quantum Physics · Physics 2024-11-27 Vu Tuan Hai , Nguyen Tan Viet , Jesus Urbaneja , Nguyen Vu Linh , Lan Nguyen Tran , Le Bin Ho

We undertake a study of the notion of a quantum graph over arbitrary finite-dimensional $C^*$-algebras $B$ equipped with arbitrary faithful states. Quantum graphs are realised principally as either certain operators on $L^2(B)$, the quantum…

Operator Algebras · Mathematics 2024-11-27 Matthew Daws

The standard model of quantum circuits assumes operations are applied in a fixed sequential "causal" order. In recent years, the possibility of relaxing this constraint to obtain causally indefinite computations has received significant…

Quantum Physics · Physics 2024-08-20 Alastair A. Abbott , Mehdi Mhalla , Pierre Pocreau

While quantum circuits built from two-particle dual-unitary (maximally entangled) operators serve as minimal models of typically nonintegrable many-body systems, the construction and characterization of dual-unitary operators themselves are…

Quantum Physics · Physics 2023-01-20 Suhail Ahmad Rather , S. Aravinda , Arul Lakshminarayan

A conjugate code pair is defined as a pair of linear codes such that one contains the dual of the other. The conjugate code pair represents the essential structure of the corresponding Calderbank-Shor-Steane (CSS) quantum code. It is argued…

Quantum Physics · Physics 2009-01-21 Mitsuru Hamada

Determining the quantum circuit complexity of a unitary operation is an important problem in quantum computation. By using the mathematical techniques of Riemannian geometry, we investigate the efficient quantum circuits in quantum…

Quantum Physics · Physics 2013-09-16 Bin Li , Zu-Huan Yu , Shao-Ming Fei

The conjugate function method is an algorithm for numerical computation of conformal mappings for simply and doubly connected domains. In this paper the conjugate function method is generalized for multiply connected domains. The key…

Numerical Analysis · Mathematics 2017-07-06 Harri Hakula , Tri Quach , Antti Rasila

Matchgates are a group of two-qubit gates associated with free fermions. They are classically simulatable if restricted to act between nearest neighbors on a one-dimensional chain, but become universal for quantum computation with…

Quantum Physics · Physics 2012-11-08 Daniel J. Brod , Ernesto F. Galvão

This work provides a quantum-computing-first derivation of the Unitary Coupled Cluster ansatz, showing that its structure emerges naturally from fermionic algebra under unitary constraints. By explicitly connecting second quantization,…

Quantum Physics · Physics 2026-04-24 Yu-Hao Chen , Renata Wong