Experimental construction of generic three-qubit states and their reconstruction from two-party reduced states on an NMR quantum information processor

Dogra, Shruti; Dorai, Kavita; Arvind, .

doi:10.1103/physreva.91.022312

Cited by 36 publications

(30 citation statements)

References 43 publications

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“…Several experimental efforts in this direction have tried to reduce the resources required to detect entanglement and have devised methods based on entanglement witnesses and positive maps to interrogate the presence of entanglement [18][19][20][21][22]. A range of experiments have been carried out to create and detect novel entangled states [23][24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Experimental detection of qubit-ququart pseudo-bound entanglement using three nuclear spins

et al. 2019

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In this work, we experimentally created and characterized a class of qubit-ququart PPT (positive under partial transpose) entangled states using three nuclear spins on an nuclear magnetic resonance (NMR) quantum information processor. Entanglement detection and characterization for systems with a Hilbert space dimension ≥ 2 ⊗ 3 is nontrivial since there are states in such systems which are both PPT as well as entangled. The experimental detection scheme that we devised for the detection of qubit-ququart PPT entanglement was based on the measurement of three Pauli operators with high precision, and is a key ingredient of the protocol in detecting entanglement. The family of PPT-entangled states considered in the current study are incoherent mixtures of five pure states. All the five states were prepared with high fidelities and the resulting PPT entangled states were prepared with mean fidelity ≥ 0.95. The entanglement thus detected was validated by carrying out full quantum state tomography (QST).

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Section: Introductionmentioning

confidence: 99%

Experimental detection of qubit-ququart pseudo-bound entanglement using three nuclear spins

et al. 2019

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“…GHZ states are not only of great interest for fundamental tests of quantum mechanics [47], but also have applications in QIP [48], quantum communications [49], error-correction protocols [50], quantum metrology [51], and high-precision spectroscopy [52]. During the past years, experimental realizations of GHZ states with eight photons using linear optical devices [53,54], fourteen ions [55], three SC qubits in circuit QED [7], five SC qubits via capacitance coupling [56], and three qubits in NMR [57] have been reported. Theoretically, proposals for generating entangled states with SC qubit circuits have been presented [58].…”

Section: Introductionmentioning

confidence: 99%

Entangling superconducting qubits in a multi-cavity system

Yang

Zheng

et al. 2016

New J. Phys.

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Important tasks in cavity quantum electrodynamics include the generation and control of quantum states of spatially separated particles distributed in different cavities. An interesting question in this context is how to prepare entanglement among particles located in different cavities, which are important for large-scale quantum information processing. We here consider a multi-cavity system where cavities are coupled to a superconducting (SC) qubit and each cavity hosts many SC qubits. We show that all intra-cavity SC qubits plus the coupler SC qubit can be prepared in an entangled Greenberger-Horne-Zeilinger (GHZ) state, by using a single operation and without the need of measurements. The GHZ state is created without exciting the cavity modes; thus greatly suppressing the decoherence caused by the cavity-photon decay and the effect of unwanted inter-cavity crosstalk on the operation. We also introduce two simple methods for entangling the intra-cavity SC qubits in a GHZ state. As an example, our numerical simulations show that it is feasible, with current circuit-QED technology, to prepare high-fidelity GHZ states, for up to nine SC qubits by using SC qubits distributed in two cavities. This proposal can in principle be used to implement a GHZ state for an arbitrary number of SC qubits distributed in multiple cavities. The proposal is quite general and can be applied to a wide range of physical systems, with the intra-cavity qubits being either atoms, NV centers, quantum dots, or various SC qubits.

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“…The two inequivalent entangled states, namely the W and GHZ states, have contrasting irreducibility features: * debmalya@iisermohali.ac.in † shrutidogra@iisermohali.ac.in ‡ kavita@iisermohali.ac.in § arvind@iisermohali.ac.in while GHZ states have irreducible correlations and cannot be determined from their two-party marginals [10,11], W-states are completely determined by their twoparty marginals [12][13][14]. Tripartite entanglement has been studied experimentally using optics [15][16][17] and NMR [18][19][20][21][22][23][24]. Recently, the entanglement properties of a permutation symmetric superposition of the W state and its obverseW = 1/ √ 3 (|100 + |101 + |110 ) have been characterized [25,26]:…”

Section: Introductionmentioning

confidence: 99%

Experimental construction of aWsuperposition state and its equivalence to the Greenberger-Horne-Zeilinger state under local filtration

et al. 2015

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We experimentally construct a novel three-qubit entangled W-superposition (WW) state on an NMR quantum information processor. We give a measurement-based filtration protocol for the invertible local operation (ILO) that converts the WW state to the GHZ state, using a register of three ancilla qubits. Further we implement an experimental protocol to reconstruct full information about the three-party WW state using only two-party reduced density matrices. An intriguing fact unearthed recently is that the WW state which is equivalent to the GHZ state under ILO, is in fact reconstructible from its two-party reduced density matrices, unlike the GHZ state. We hence demonstrate that although the WW state is interconvertible with the GHZ state, it stores entanglement very differently.

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Experimental construction of generic three-qubit states and their reconstruction from two-party reduced states on an NMR quantum information processor

Cited by 36 publications

References 43 publications

Experimental detection of qubit-ququart pseudo-bound entanglement using three nuclear spins

Experimental detection of qubit-ququart pseudo-bound entanglement using three nuclear spins

Entangling superconducting qubits in a multi-cavity system

Experimental construction of aWsuperposition state and its equivalence to the Greenberger-Horne-Zeilinger state under local filtration

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