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The accessible information decreases under quantum operations. We analyzed the connection between quantum operations and accessible information. We show that a general quantum process cannot be operated accurately. Futhermore, an unknown…

Quantum Physics · Physics 2007-05-23 Qing-yu Cai

Universal quantum computation requires the implementation of arbitrary control operations on the quantum register. In most cases, this is achieved by external control fields acting selectively on each qubit to drive single-qubit operations.…

Quantum Physics · Physics 2015-06-19 Jingfu Zhang , Daniel Burgarth , Raymond Laflamme , Dieter Suter

According to a fundamental result in quantum computing, any unitary transformation on a composite system can be generated using so-called 2-local unitaries that act only on two subsystems. Beyond its importance in quantum computing, this…

Quantum Physics · Physics 2024-08-15 Iman Marvian

Quantum states obey an asymptotic no-cloning theorem, stating that no deterministic machine can reliably replicate generic sequences of identically prepared pure states. In stark contrast, we show that generic sequences of unitary gates can…

Quantum Physics · Physics 2015-04-01 G. Chiribella , Y. Yang , C. Huang

We study how two pieces of localized quantum information can be delocalized across a composite Hilbert space when a global unitary operation is applied. We classify the delocalization power of global unitary operations on quantum…

Quantum Physics · Physics 2010-06-09 Akihito Soeda , Mio Murao

Quantum discord is significant in analyzing quantum nonclassicality beyond the paradigm of entanglement. Presently we have explored the effectiveness of global unitary operations in manifesting quantum discord from a general two qubit zero…

Quantum Physics · Physics 2021-03-17 Kaushiki Mukherjee , Biswajit Paul , Sumana Karmakar

Unitary operations are a fundamental component of quantum algorithms, but they seem to be far more useful if given with a "quantum control" as a controlled unitary operation. However, quantum operations are not limited to unitary…

Quantum Physics · Physics 2021-06-16 Qingxiuxiong Dong , Shojun Nakayama , Akihito Soeda , Mio Murao

We report a deterministic and exact protocol to reverse any unknown qubit-unitary operation, which simulates the time inversion of a closed qubit system. To avoid known no-go results on universal deterministic exact unitary inversion, we…

Quantum Physics · Physics 2023-09-21 Satoshi Yoshida , Akihito Soeda , Mio Murao

Any technology for quantum information processing (QIP) must embody within it quantum bits (qubits) and maintain control of their key quantum properties of superposition and entanglement. Typical QIP schemes envisage an array of physical…

Quantum Physics · Physics 2009-11-13 Joseph Fitzsimons , Li Xiao , Simon C. Benjamin , Jonathan A. Jones

Quantum computing can provide speedups in solving many problems as the evolution of a quantum system is described by a unitary operator in an exponentially large Hilbert space. Such unitary operators change the phase of their eigenstates…

Quantum Physics · Physics 2024-01-23 Youle Wang , Lei Zhang , Zhan Yu , Xin Wang

This paper addresses the problem of designing universal quantum circuits to transform $k$ uses of a $d$-dimensional unitary input-operation into a unitary output-operation in a probabilistic heralded manner. Three classes of protocols are…

Quantum Physics · Physics 2020-04-16 Marco Túlio Quintino , Qingxiuxiong Dong , Atsushi Shimbo , Akihito Soeda , Mio Murao

Unknown unitary inversion is a fundamental primitive in quantum computing and physics. Although recent work has demonstrated that quantum algorithms can invert arbitrary unknown unitaries without accessing their classical descriptions,…

Quantum Physics · Physics 2025-06-26 Yin Mo , Tengxiang Lin , Xin Wang

We consider quantum circuits composed of single-qubit operations and global entangling gates generated by Ising-type Hamiltonians. It is shown that such circuits can implement a large class of unitary operators commonly used in quantum…

Quantum Physics · Physics 2022-12-02 Sergey Bravyi , Dmitri Maslov , Yunseong Nam

In order to investigate distributed quantum computation under restricted network resources, we introduce a quantum computation task over the butterfly network where both quantum and classical communications are limited. We consider…

Quantum Physics · Physics 2011-07-29 Akihito Soeda , Yoshiyuki Kinjo , Peter S. Turner , Mio Murao

We present a general, systematic, and efficient method for decomposing any given exponential operator of bosonic mode operators, describing an arbitrary multi-mode Hamiltonian evolution, into a set of universal unitary gates. Although our…

Quantum Physics · Physics 2011-10-19 Seckin Sefi , Peter van Loock

Quantum gates executed on physical hardware are inevitably degraded by environmental noise. While state purification effectively distills static quantum resources, the dynamic execution of quantum algorithms requires a higher-order approach…

Quantum Physics · Physics 2026-04-02 Jiayi Zhao , Yu-Ao Chen , Guocheng Zhen , Chengkai Zhu , Ranyiliu Chen , Xin Wang

Many promising ideas for quantum computing demand the experimental ability to directly switch 'on' and 'off' a physical coupling between the component qubits. This is typically the key difficulty in implementation, and precludes quantum…

Quantum Physics · Physics 2009-11-07 Simon C. Benjamin , Sougato Bose

The paradigm behind digital quantum computing inherits the idea of using binary information processing. Nature in fact gives much more rich structures of physical objects that can be used for encoding information, which is especially…

Quantum Physics · Physics 2025-06-04 Evgeniy O. Kiktenko , Anastasiia S. Nikolaeva , Aleksey K. Fedorov

Quantum error-correcting codes are many-body entangled states that are prepared and measured using complex sequences of entangling operations. Each element of such an entangling sequence introduces noise to delicate quantum information…

An algorithm is proposed to convert arbitrary unitary matrix to a sequence of $X$ gates and fully controlled $R_y, R_z$ and $R_1$ gates. This algorithm is used to generate Q# implementation for arbitrary unitary matrix. Some optimizations…

Quantum Physics · Physics 2025-01-15 Dmytro Fedoriaka