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We employ a nuclear magnetic resonance (NMR) quantum information processor to simulate the ground state of an XXZ spin chain and measure its NMR analog of entanglement, or pseudo-entanglement. The observed pseudo-entanglement for a…

Quantum Physics · Physics 2011-07-26 Jingfu Zhang , Tzu-Chieh Wei , Raymond Laflamme

We report the realization of a nuclear magnetic resonance (NMR) quantum computer which combines the quantum Fourier transform (QFT) with exponentiated permutations, demonstrating a quantum algorithm for order-finding. This algorithm has the…

We discuss the ensemble version of the Deutsch-Jozsa (DJ) algorithm which attempts to provide a "scalable" implementation on an expectation-value NMR quantum computer. We show that this ensemble implementation of the DJ algorithm is at best…

Quantum Physics · Physics 2016-09-08 Arvind , David Collins

Entanglement forging based variational algorithms leverage the bi-partition of quantum systems for addressing ground state problems. The primary limitation of these approaches lies in the exponential summation required over the numerous…

The advent of digital neutral-atom quantum computers relies on the development of fast and robust protocols for high-fidelity quantum operations. In this work, we introduce a novel scheme for entangling gates using four atomic levels per…

Quantum Physics · Physics 2025-07-22 Giuliano Giudici , Stefano Veroni , Giacomo Giudice , Hannes Pichler , Johannes Zeiher

The first optical proposal for the realization of the two-bit version of the Deutsch-Jozsa algorithm [D. Deutsch and R. Jozsa, Proc. R. Soc. London A {\bf 493}, 553 (1992)] is presented. The proposal uses Stark shifts in an ensemble of…

Quantum Physics · Physics 2007-05-23 Shubhrangshu Dasgupta , G. S. Agarwal

This thesis addresses the problems of initialization and separability in liquid state NMR based quantum information processors. We prepare pure quantum states lying above the entanglement threshold. Our pure state quantum computer derives…

Quantum Physics · Physics 2007-05-23 M. S. Anwar

We propose a way to implement a three-qubit refined Deutsh-Jozsa (DJ) algorithm. The present proposal is based on the construction of the 35 $f$-controlled phase gates, which uses single-qubit $\sigma_z$ gates and two-qubit {\it standard}…

Quantum Physics · Physics 2015-06-16 Qi-Ping Su , Man Liu , Chui-Ping Yang

Quantum computing using two-dimensional NMR has recently been described using scalar coupling evolution technique [J. Chem. Phys.,109,10603 (1998)]. In the present paper, we describe two-dimensional NMR quantum computing with the help of…

Quantum Physics · Physics 2007-05-23 T. S. Mahesh , Kavita Dorai , Arvind , Anil Kumar

The phenomenon of quantum entanglement is fundamental to the implementation of quantum computation, and requires at least two qubits for its demonstration. However, both Deutsch algorithm and Grover's search algorithm for two bits do not…

Quantum Physics · Physics 2007-05-23 Arvind , N. Mukunda

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 study the deep multi-scale entanglement renormalization ansatz (DMERA) on quantum hardware and the causal cone of a subset of the qubits which make up the ansatz. This causal cone spans $O(M+\log{N})$ physical qubits on a quantum device,…

Quantum Physics · Physics 2025-06-23 Kushagra Garg , Zeeshan Ahmed , Andreas Thomasen

We discuss a new approach to simulate quantum algorithms using classical probabilistic bits and circuits. Each qubit (a two-level quantum system) is initially mapped to a vector in an eight dimensional probability space (equivalently, to a…

Quantum Physics · Physics 2023-07-28 D. D. Yavuz , A. Yadav

We propose a way for generating $n$-qubit Greenberger-Horne-Zeilinger (GHZ) entangled states with a three-level qubit system and (n-1) four-level qubit systems in a cavity. This proposal does not require identical qubit-cavity coupling…

Quantum Physics · Physics 2015-05-28 Chui-Ping Yang

We propose a protocol to construct the 35 $f$-controlled phase gates of a three-qubit refined Deutsch-Jozsa (DJ) algorithm, by using single-qubit $\sigma_z$ gates, two-qubit controlled phase gates, and two-target-qubit controlled phase…

Quantum Physics · Physics 2016-02-25 Qi-Ping Su , Chui-Ping Yang

Quantum computing implementations under consideration today typically deal with systems with microscopic degrees of freedom such as photons, ions, cold atoms, and superconducting circuits. The quantum information is stored typically in…

Quantum Physics · Physics 2016-05-04 Henry Semenenko , Tim Byrnes

We propose a method for quantum algorithm design assisted by machine learning. The method uses a quantum-classical hybrid simulator, where a "quantum student" is being taught by a "classical teacher." In other words, in our method, the…

Quantum Physics · Physics 2014-07-18 Jeongho Bang , Junghee Ryu , Seokwon Yoo , Marcin Pawlowski , Jinhyoung Lee

We show how to divide a coupled multi-spin system into a small subset of ``active'' spins that evolve under chemical shift or scalar coupling operators, and a larger subset of ``spectator'' spins which are returned to their initial states,…

Quantum Physics · Physics 2009-10-31 N Linden , H Barjat , RJ Carbajo , R Freeman

By choosing H nucleus in Carbon-13 labelled trichloroethylene as one qubit environment, and two C nuclei as a two-qubit system, we have simulated quantum decoherence when the system lies in an entangled state using nuclear magnetic…

Quantum Physics · Physics 2009-09-29 Jingfu Zhang , Zhiheng Lu , Lu Shan , Zhiwei Deng

Going beyond the entanglement of microscopic objects (such as photons, spins, and ions), here we propose an efficient approach to produce and control the quantum entanglement of three macroscopic coupled superconducting qubits. By…

Quantum Physics · Physics 2009-11-11 L. F. Wei , Yu-xi Liu , Franco Nori