Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:0909.2743 · Physical Review A

Experimental generation of pseudo-bound-entanglement

Hermann Kampermann, Dagmar Bruß, Xinhua Peng, Dieter Suter

Published Apr 30, 2010• 31 citations
arXivHTMLPDF

Abstract

We use nuclear magnetic resonance to experimentally generate a bound-entangled (more precisely: pseudo-bound-entangled) state, i.e., a quantum state which is nondistillable but nevertheless entangled. Our quantum system consists of three qubits. We characterize the produced state via state tomography to show that the created state has a positive partial transposition with respect to any bipartite splitting, and we use a witness operator to prove its pseudoentanglement.

DOI
10.1103/physreva.81.040304

Related papers

Generation and detection of bound entanglement

P. Hyllus, Carolina Alves, Dagmar Bruß +1 more

We propose a method for the experimental generation of two different families of bound entangled states of three qubits. Our method is based on the explicit construction of a quantum network that produces a purification of the desired state. We also suggest a route for the experimental detection of bound entanglement, by employing a witness operator plus a test of the positivity of the partial transposes.

arXiv:quant-ph/0405164•Physical Review A•Sep 21, 2004•34 citations

Generation of bipartite bound entanglement

Frank E. S. Steinhoff

We introduce a class of entangled bipartite states that are positive under partial transposition operation,i.e., PPT bound entangled states. These states are based on realistical preparation procedures in optical systems, being thus a feasible option to generate and observe bipartite bound entanglement in high precision experiments. The method employed to detect entanglement has the advantages of being simple, analitical and independent of the range criterion. We also link PPT property of one-mode states that pass a beam-splitter to Hankel operator theory and related moment problems.

Physicae Proceedings•Mar 29, 2012•0 citations

Creation and control of entanglement in condensed matter spin systems

Stephanie Simmons

The highly parallel nature of the fundamental principles of quantum mechanics means that certain key resource-intensive tasks --- including searching, code decryption and medical, chemical and material simulations --- can be computed polynomially or even exponentially faster with a quantum computer. In spite of its remarkably fast development, the field of quantum computing is still young, and a large-scale prototype using any one of the candidate quantum bits (or 'qubits') under investigation has yet to be developed. Spin-based qubits in condensed matter systems are excellent candidates. Spins controlled using magnetic resonance have provided the first, most advanced, and highest fidelity experimental demonstrations of quantum algorithms to date. Despite having highly promising control characteristics, most physical ensembles investigated using magnetic resonance are unable to produce entanglement, a critical missing ingredient for a pure-state quantum computer. Quantum objects are said to be entangled if they cannot be described individually: they remain fundamentally linked regardless of their physical separation. Such highly non-classical states can be exploited for a host of quantum technologies including teleportation, metrology, and quantum computation. Here I describe how to experimentally create, control and characterise entangled quantum ensembles using magnetic resonance. I first explore the relationship between entanglement and quantum metrology and demonstrate a sensitivity enhancement over classical resources using molecular sensors controlled with liquid-state nuclear magnetic resonance. I then examine the computational potential of irreversible relaxation processes in combination with traditional reversible magnetic resonance control techniques. I show how irreversible processes can polarise both nuclear and electronic spins, which improves the quality of qubit initialisation. I discuss the process of quantum state tomography, where an arbitrary quantum state can be accurately measured and characterised, including components which go undetected using traditional magnetic resonance techniques. Lastly, I combine the above findings to initialise, create and characterise entanglement between an ensemble of electron and nuclear spin defects in silicon. I further this by generating pseudo-entanglement between an ensemble of nuclear spins mediated by a transient electron spin in a molecular system. These findings help pave the way towards a particular architecture for a scalable, spin-based quantum computer.

•Jan 1, 2011•3 citations

Non-full-rank bound entangled states satisfying the range criterion

Somshubhro Bandyopadhyay, Sibasish Ghosh A, Vwani Roychowdhury

A systematic method for generating bound entangled states in any bipartite system, with ranks ranging from five to full rank, is presented. These states are constructed by mixing separable states with unextendable product basis--generated bound entangled states that are positive under partial transposition (PPT). A subset of this class of PPT bound entangled states, having less than full rank, is shown to satisfy the range criterion [P. Horodecki, Phys. Lett. A 232, 333 (1997)].

arXiv:quant-ph/0406023•Physical Review A•Jan 12, 2005•29 citations

Attainable entanglement of unitary transformed thermal states in liquid-state nuclear magnetic resonance with the chemical shift

Yukihiro Ota, Shuji Mikami, Motoyuki Yoshida +1 more

Recently, Yu, Brown, and Chuang [Phys. Rev. A {\bf 71}, 032341 (2005)] investigated the entanglement attainable from unitary transformed thermal states in liquid-state nuclear magnetic resonance (NMR). Their research gave an insight into the role of the entanglement in a liquid-state NMR quantum computer. Moreover, they attempted to reveal the role of mixed-state entanglement in quantum computing. However, they assumed that the Zeeman energy of each nuclear spin which corresponds to a qubit takes a common value for all; there is no chemical shift. In this paper, we research a model with the chemical shifts and analytically derive the physical parameter region where unitary transformed thermal states are entangled, by the positive partial transposition (PPT) criterion with respect to any bipartition. We examine the effect of the chemical shifts on the boundary between the separability and the nonseparability, and find it is negligible.

arXiv:quant-ph/0612158•Journal of Physics A Mathematical and Theoretical•Nov 6, 2007•0 citations

Construction of three-qubit genuine entanglement with bipartite positive partial transposes

Kil-Chan Ha, Seung-Hyeok Kye

We construct triqubit genuinely entangled states which have positive partial transposes (PPTs) with respect to the bipartition of systems. These examples disprove a conjecture [Novo, Moroder, and G\"uhne, Phys. Rev A 88, 012305 (2013)] which claims that PPT mixtures are necessary and sufficient for the biseparability of three qubits.

arXiv:1512.04693•Physical Review A•Mar 11, 2016•9 citations
We use nuclear magnetic resonance to experimentally generate a bound-entangled (more precisely: pseudo-bound-entangled) state, i.e., a quantum state which is nondistillable but nevertheless entangled. Our quantum system consists of three qubits. We characterize the produced state via state tomography to show that the created state has a positive partial transposition with respect to any bipartite splitting, and we use a witness operator to prove its pseudoentanglement.
We introduce a class of entangled bipartite states that are positive under partial transposition operation,i.e., PPT bound entangled states. These states are based on realistical preparation procedures in optical systems, being thus a feasible option to generate and observe bipartite bound entanglement in high precision experiments. The method employed to detect entanglement has the advantages of being simple, analitical and independent of the range criterion. We also link PPT property of one-mode states that pass a beam-splitter to Hankel operator theory and related moment problems.
The highly parallel nature of the fundamental principles of quantum mechanics means that certain key resource-intensive tasks --- including searching, code decryption and medical, chemical and material simulations --- can be computed polynomially or even exponentially faster with a quantum computer. In spite of its remarkably fast development, the field of quantum computing is still young, and a large-scale prototype using any one of the candidate quantum bits (or 'qubits') under investigation has yet to be developed. Spin-based qubits in condensed matter systems are excellent candidates. Spins controlled using magnetic resonance have provided the first, most advanced, and highest fidelity experimental demonstrations of quantum algorithms to date. Despite having highly promising control characteristics, most physical ensembles investigated using magnetic resonance are unable to produce entanglement, a critical missing ingredient for a pure-state quantum computer. Quantum objects are said to be entangled if they cannot be described individually: they remain fundamentally linked regardless of their physical separation. Such highly non-classical states can be exploited for a host of quantum technologies including teleportation, metrology, and quantum computation. Here I describe how to experimentally create, control and characterise entangled quantum ensembles using magnetic resonance. I first explore the relationship between entanglement and quantum metrology and demonstrate a sensitivity enhancement over classical resources using molecular sensors controlled with liquid-state nuclear magnetic resonance. I then examine the computational potential of irreversible relaxation processes in combination with traditional reversible magnetic resonance control techniques. I show how irreversible processes can polarise both nuclear and electronic spins, which improves the quality of qubit initialisation. I discuss the process of quantum state tomography, where an arbitrary quantum state can be accurately measured and characterised, including components which go undetected using traditional magnetic resonance techniques. Lastly, I combine the above findings to initialise, create and characterise entanglement between an ensemble of electron and nuclear spin defects in silicon. I further this by generating pseudo-entanglement between an ensemble of nuclear spins mediated by a transient electron spin in a molecular system. These findings help pave the way towards a particular architecture for a scalable, spin-based quantum computer.
Recently, Yu, Brown, and Chuang [Phys. Rev. A {\bf 71}, 032341 (2005)] investigated the entanglement attainable from unitary transformed thermal states in liquid-state nuclear magnetic resonance (NMR). Their research gave an insight into the role of the entanglement in a liquid-state NMR quantum computer. Moreover, they attempted to reveal the role of mixed-state entanglement in quantum computing. However, they assumed that the Zeeman energy of each nuclear spin which corresponds to a qubit takes a common value for all; there is no chemical shift. In this paper, we research a model with the chemical shifts and analytically derive the physical parameter region where unitary transformed thermal states are entangled, by the positive partial transposition (PPT) criterion with respect to any bipartition. We examine the effect of the chemical shifts on the boundary between the separability and the nonseparability, and find it is negligible.