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In noisy intermediate-scale quantum computing, the limited scalability of a single quantum processing unit (QPU) can be extended through distributed quantum computing (DQC), in which one can implement global operations over two QPUs by…

Hypergraph states form a family of multiparticle quantum states that generalizes cluster states and graph states. We study the action and graphical representation of nonlocal unitary transformations between hypergraph states. This leads to…

Quantum Physics · Physics 2017-04-17 Mariami Gachechiladze , Nikoloz Tsimakuridze , Otfried Gühne

The power of a quantum circuit is determined through the number of two-qubit entangling gates that can be performed within the coherence time of the system. In the absence of parallel quantum gate operations, this would make the quantum…

Quantum Physics · Physics 2021-05-26 Rozhin Yousefjani , Abolfazl Bayat

We present two quantum state sharing protocols where the channels are not maximally entangled states. By properly choosing the measurement basis it is possible to achieve unity fidelity transfer of the state if the parties collaborate. We…

Quantum Physics · Physics 2009-11-13 Goren Gordon , Gustavo Rigolin

We address the problem of the generation of entanglement. We focus on the control of entanglement shared by two non-interacting parties $A$ and $C$ via interaction with a third party $B$. We show that, for certain physical models, it is…

Quantum Physics · Physics 2007-05-23 Peter Stelmachovic , Marian Rosko

We propose a modular quantum computation architecture based on utilizing multipartite entanglement. Each module consists of a small-scale quantum computer comprising data, memory and entangling qubits. Entangling qubits are used to…

Quantum Physics · Physics 2024-12-16 Ferran Riera-Sàbat , Wolfgang Dür

A single-shot Toffoli, or controlled-controlled-NOT, gate is desirable for classical and quantum information processing. The Toffoli gate alone is universal for reversible computing and, accompanied by the Hadamard gate, forms a universal…

Quantum Physics · Physics 2015-05-21 Ehsan Zahedinejad , Joydip Ghosh , Barry C. Sanders

The information obtained from the operation of a quantum gate on only two complementary sets of input states is sufficient to estimate the quantum process fidelity of the gate. In the case of entangling gates, these conditions can be used…

Quantum Physics · Physics 2017-08-23 Holger F. Hofmann , Ryo Okamoto , Shigeki Takeuchi

Controlled quantum gates play a crucial role in enabling quantum universal operations by facilitating interactions between qubits. Direct implementation of three-qubit gates simplifies the design of quantum circuits, thereby being conducive…

Quantum Physics · Physics 2024-11-27 Qianke Wang , Dawei Lyu , Jun Liu , Jian Wang

We propose an efficiently measurable lower bound on quantum process fidelity of N-qubit controlled-Z gates. This bound is determined by average output state fidelities for N partially conjugate product bases. A distinct advantage of our…

We develop the probabilistic implementation of a nonlocal gate $\exp{[i\xi{\sigma_{n_A}}\sigma_{n_B}]}$ and $\xi\in[0,\frac\pi4]$, by using a single non-maximally entangled state. We prove that, nonlocal gates can be implemented with a…

Quantum Physics · Physics 2009-11-11 Lin Chen , Yi-Xin Chen

We study the remote implementation of a unitary transformation on a qubit. We show the existence of non-trivial protocols (i.e., using less resources than bidirectional state teleportation) which allow the perfect remote implementation of…

Quantum Physics · Physics 2009-11-07 S. F. Huelga , M. B. Plenio , J. A. Vaccaro

We propose and study a method for using non-maximally entangled states to implement probabilistically non-local gates. Unlike distillation-based protocols, this method does not generate a maximally entangled state at intermediate stages of…

Quantum Physics · Physics 2007-05-23 Berry Groisman , Benni Reznik

Compared with the idea of universal quantum computation, a direct synthesis of a multiqubit logic gate can greatly improve the efficiency of quantum information processing tasks. Here we propose an efficient scheme to implement a…

Quantum Physics · Physics 2020-12-02 H. D. Yin , X. X. Li , G. C. Wang , X. Q. Shao

Controlled unitary gates are a basic element in many quantum algorithms. Converting a general unitary $U$ with a known decomposition into its controlled version, controlled-$U$, can introduce a large overhead in terms of the depth of the…

Quantum Physics · Physics 2026-02-24 Carlos Navas-Merlo , Juan Carlos García-Escartín

Parallel processing of information plays a critical role in accelerating computation. This includes quantum computers, where parallel processing of quantum information will play a critical role in practical quantum advantage. Here, we…

In certain cases the communication time required to deterministically implement a nonlocal bipartite unitary using prior entanglement and LOCC (local operations and classical communication) can be reduced by a factor of two. We introduce…

Quantum Physics · Physics 2013-05-30 Li Yu , Robert B. Griffiths , Scott M. Cohen

We put forward a strategy to encode a quantum operation into the unmodulated dynamics of a quantum network without the need of external control pulses, measurements or active feedback. Our optimization scheme, inspired by supervised machine…

Quantum Physics · Physics 2016-07-21 Leonardo Banchi , Nicola Pancotti , Sougato Bose

Understanding entanglement cost in non-local quantum computation (NLQC) is relevant to complexity, cryptography, gravity, and other areas. This entanglement cost is largely uncharacterized; previous lower bound techniques apply to narrowly…

Quantum Physics · Physics 2026-05-01 Richard Cleve , Alex May

Quantifying the entanglement generation of a multipartite unitary operation is a key problem in quantum information processing. We introduce the definition of multipartite entangling, assisted entangling, and disentangling power, which is a…

Quantum Physics · Physics 2024-10-22 Xinyu Qiu , Zhiwei Song , Lin Chen