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In many quantum information processing applications, it is important to be able to transfer a quantum state from one location to another - even within a local device. Typical approaches to implement the quantum state transfer rely on…

Quantum Physics · Physics 2018-10-09 Yuichiro Matsuzaki , Victor M. Bastidas , Yuki Takeuchi , William J. Munro , Shiro Saito

We present a new robust decoupling scheme suitable for levels with either half integer or integer angular momentum states. Through continuous dynamical decoupling techniques, we create a protected qubit subspace, utilizing a multi-state…

Quantum Physics · Physics 2014-04-29 N. Aharon , M. Drewsen , A. Retzker

We propose a deterministic scheme of generating genuine multiparty entangled states in quantum networks of arbitrary size having various geometric structures -- we refer to it as entanglement circulation. The procedure involves optimization…

Quantum Physics · Physics 2022-09-16 Pritam Halder , Ratul Banerjee , Srijon Ghosh , Amit Kumar Pal , Aditi Sen De

Quantum algorithms for diverse problems, including search and optimization problems, require the implementation of a reflection operator over a target state. Commonly, such reflections are approximately implemented using phase estimation.…

Quantum Physics · Physics 2018-03-08 Anirban Narayan Chowdhury , Yigit Subasi , Rolando D. Somma

We provide a reformulation of finite dimensional quantum theory in the circuit framework in terms of mathematical axioms, and a reconstruction of quantum theory from operational postulates. The mathematical axioms for quantum theory are the…

Quantum Physics · Physics 2011-08-26 Lucien Hardy

We propose a scheme for encoding many qubits in a single rotor, that is, a continuous and periodic degree of freedom. A key feature of this scheme is its ability to manipulate and entangle the encoded qubits with a single operation on the…

Quantum Physics · Physics 2015-05-18 Amir Kalev , Philippe Raynal , Jun Suzuki , Berthold-Georg Englert

We present a simple quantum circuit that allows for the universal and deterministic manipulation of the quantum state of confined harmonic oscillators. The scheme is based on the selective interactions of the referred oscillator with an…

Quantum Physics · Physics 2007-05-23 Marcelo Franca Santos

In this paper we present results illustrating the power and flexibility of one-bit teleportations in quantum bus computation. We first show a scheme to perform a universal set of gates on continuous variable modes, which we call a quantum…

Quantum Physics · Physics 2010-04-23 Marcus Silva , Casey R. Myers

The whole Hilbert state space of an n-qubit spin system can be divided into (n+1) state subspaces according to the angular momentum theory of quantum mechanics. Here it is shown that any unknown state in such a state subspace, whose…

Quantum Physics · Physics 2016-09-08 Xijia Miao

We present a new algorithm for reducing an arbitrary unitary matrix into a sequence of elementary operations (operations such as controlled-nots and qubit rotations). Such a sequence of operations can be used to manipulate an array of…

Quantum Physics · Physics 2007-05-23 Robert R. Tucci

We develop a technique for single qubit quantum state tomography using the mathematical setup of generalized quantization scheme for games. In our technique Alice sends an unknown pure quantum state to Bob who appends it with |0><0| and…

Quantum Physics · Physics 2011-07-28 Ahmad Nawaz

Quantum state tomography (QST) for reconstructing pure states requires exponentially increasing resources and measurements with the number of qubits by using state-of-the-art quantum compressive sensing (CS) methods. In this article, QST…

Quantum Physics · Physics 2021-11-16 Burhan Gulbahar

We consider the problem of reversing quantum dynamics, with the goal of preserving an initial state's quantum entanglement or classical correlation with a reference system. We exhibit an approximate reversal operation, adapted to the…

Quantum Physics · Physics 2026-01-21 H. Barnum , E. Knill

Quantum reservoir computing has emerged as a promising machine learning paradigm for processing temporal data on near-term quantum devices, as it allows for exploiting the large computational capacity of the qubits without suffering from…

Quantum Physics · Physics 2025-08-21 Emanuele Ricci , Francesco Monzani , Luca Nigro , Enrico Prati

Realizing non-unitary transformations on unitary-gate based quantum devices is critically important for simulating a variety of physical problems including open quantum systems and subnormalized quantum states. We present a dilation based…

Within the general context of the architecture in quantum computer design, this paper aims is to provide a general strategy to obtain a block-matrix representation of quantum gates applied to qubits placed in arbitrary positions over an…

Quantum Physics · Physics 2017-11-28 Giuseppe Sergioli

Quantum operations provide a general description of the state changes allowed by quantum mechanics. Simple necessary and sufficient conditions for an ideal quantum operation to be reversible by a unitary operation are derived in this paper.…

Quantum Physics · Physics 2009-10-30 M. A. Nielsen , Carlton M. Caves

Grover's algorithm is a quantum search algorithm that proceeds by repeated applications of the Grover operator and the Oracle until the state evolves to one of the target states. In the standard version of the algorithm, the Grover operator…

Quantum Physics · Physics 2018-03-14 Tim Byrnes , Gary Forster , Louis Tessler

Quantum states can be used to encode the information contained in a direction, i.e., in a unit vector. We present the best encoding procedure when the quantum state is made up of $N$ spins (qubits). We find that the quality of this optimal…

Quantum Physics · Physics 2009-11-06 E. Bagan , M. Baig , A. Brey , R. Munoz-Tapia , R. Tarrach

We perform optimal-control-theory calculations to determine the minimum number of two-qubit CNOT gates needed to perform quantum state preparation and unitary operator synthesis for few-qubit systems. By considering all possible gate…

Quantum Physics · Physics 2022-08-24 Sahel Ashhab , Naoki Yamamoto , Fumiki Yoshihara , Kouichi Semba
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