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Related papers: Scalable estimation of pure multi-qubit states

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In almost all quantum applications, one of the key steps is to verify that the fidelity of the prepared quantum state meets expectations. In this Letter, we propose a new approach solving this problem using machine-learning techniques.…

Quantum Physics · Physics 2021-09-28 Xiaoqian Zhang , Maolin Luo , Zhaodi Wen , Qin Feng , Shengshi Pang , Weiqi Luo , Xiaoqi Zhou

For any finite dimensional Hilbert space, we construct explicitly five orthonormal bases such that the corresponding measurements allow for efficient tomography of an arbitrary pure quantum state. This means that such measurements can be…

Quantum Physics · Physics 2016-09-14 Claudio Carmeli , Teiko Heinosaari , Michael Kech , Jussi Schultz , Alessandro Toigo

We undertake experimental detection of the entanglement present in arbitrary three-qubit pure quantum states on an NMR quantum information processor. Measurements of only four observables suffice to experimentally differentiate between the…

Quantum Physics · Physics 2018-09-06 Amandeep Singh , Harpreet Singh , Kavita Dorai , Arvind

We propose a scalable scheme for optical quantum computing using measurement-induced continuous-variable quantum gates in a loop-based architecture. Here, time-bin-encoded quantum information in a single spatial mode is deterministically…

Quantum Physics · Physics 2017-09-27 Shuntaro Takeda , Akira Furusawa

Separability and entanglement for n-qubits systems are quantified by using Hilbert-Schmidt (HS) decompositions in which the density matrices are decomposed into various terms representing certain one qubit, two-qubits,and larger qubits…

Quantum Physics · Physics 2016-02-23 Y. Ben-Aryeh

Many quantum states arising in algorithms and physical systems occupy only a small, structured subset of the exponentially large Hilbert space, yet standard quantum state tomography fails to exploit this structure. We present an efficient…

Quantum Physics · Physics 2025-12-24 Chi-Kwong Li , Kevin Yipu Wu , Zherui Zhang

In this work we study the entanglement of pure fourpartite of qubit states. The analysis is realized through the comparison between two different entanglement measures: the Groverian entanglement measure and the residual entanglement…

Quantum Physics · Physics 2009-02-04 David Sena Oliveira , Rubens Viana Ramos

We describe and analyze an efficient register-based hybrid quantum computation scheme. Our scheme is based on probabilistic, heralded optical connection among local five-qubit quantum registers. We assume high fidelity local unitary…

Quantum Physics · Physics 2007-12-27 Liang Jiang , Jacob M. Taylor , Anders S. Sørensen , Mikhail D. Lukin

Many-body quantum systems can be characterised using the notions of \emph{k}-separability and entanglement depth. A quantum state is \emph{k}-separable if it can be expressed as a mixture of \emph{k} entangled subsystems, and its…

We demonstrate the deterministic generation of multipartite entanglement based on scalable methods. Four qubits are encoded in $^{40}$Ca$^+$, stored in a micro-structured segmented Paul trap. These qubits are sequentially entangled by…

The Measurement Based Quantum Computation (MBQC) model achieves universal quantum computation by employing projective single qubit measurements with classical feedforward on a highly entangled multipartite cluster state. Rapid advances in…

Quantum Physics · Physics 2021-12-23 Swapnil Nitin Shah

In this article we propose a method to estimate with high accuracy pure quantum states of a single qudit. Our method is based on the minimization of the squared error between the complex probability amplitudes of the unknown state and its…

Quantum Physics · Physics 2021-07-14 A. Rojas , L. Pereira , S. Niklitschek , A. Delgado

We propose a quantum computation architecture of double-dot molecules, where the qubit is encoded in the molecule two-electron spin states. By arranging the two dots inside each molecule perpendicular to the qubit scaling line, the…

Quantum Physics · Physics 2009-11-13 Hui Zhang , Guo-Ping Guo , Tao Tu , Guang-Can Guo

The n-qubit real equally weighted states are employed in some quantum algorithms including Deutsch-Jozsa, Grover, Simon, and so on. We qualitatively investigate the entanglement properties of n-qubit real equally weighted states. Firstly,…

Quantum Physics · Physics 2012-07-12 Ri Qu , Yanru Bao

We investigate several aspects of realizing quantum computation using entangled polar molecules in pendular states. Quantum algorithms typically start from a product state |00...0> and we show that up to a negligible error, the ground…

Quantum Physics · Physics 2016-07-19 Qi Wei , Yudong Cao , Sabre Kais , Bretislav Friedrich , Dudley Herschbach

The determination of the state fidelity and the detection of entanglement are fundamental problems in quantum information experiments. We investigate how these goals can be achieved with a minimal effort. We show that the fidelity of GHZ…

Quantum Physics · Physics 2008-09-27 Otfried Gühne , Chao-Yang Lu , Wei-Bo Gao , Jian-Wei Pan

We investigate whether pure entangled states can be associated to a measurement basis in which all vectors are local unitary transformations of the original state. We prove that for bipartite states with a local dimension that is either $2,…

Quantum Physics · Physics 2023-08-28 Florian Pimpel , Martin J. Renner , Armin Tavakoli

Quantum computers are now on the brink of outperforming their classical counterparts. One way to demonstrate the advantage of quantum computation is through quantum random sampling performed on quantum computing devices. However, existing…

We describe and analyze algorithms for classically simulating measurement of an $n$-qubit quantum state $\psi$ in the standard basis, that is, sampling a bit string $x$ from the probability distribution $|\langle x|\psi\rangle|^2$. Our…

Quantum Physics · Physics 2022-06-15 Sergey Bravyi , David Gosset , Yinchen Liu

An adaptive method for quantum state fidelity estimation in bipartite higher dimensional systems is established. This method employs state verifier operators which are constructed by local POVM operators and adapted to the measurement…

Quantum Physics · Physics 2020-09-17 Jun-Yi Wu
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