References of "Bastin, Thierry"
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See detailEntanglement robustness against particle loss in multiqubit systems
Neven, Antoine ULiege; Martin, John ULiege; Bastin, Thierry ULiege

in Physical Review. A (2018), 98

When some of the parties of a multipartite entangled pure state are lost, the question arises whether the residual mixed state is also entangled, in which case the initial entangled pure state is said to ... [more ▼]

When some of the parties of a multipartite entangled pure state are lost, the question arises whether the residual mixed state is also entangled, in which case the initial entangled pure state is said to be robust against particle loss. In this paper, we investigate this entanglement robustness for N-qubit pure states. We identify exhaustively all entangled states that are fragile, i.e., not robust, with respect to the loss of any single qubit of the system. We also study the entanglement robustness properties of symmetric states and put these properties in the perspective of the classification of states with respect to stochastic local operations assisted with classic communication (SLOCC classification). [less ▲]

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See detailMagneto-optical trapping of iron atoms: temperature measurement
Petit, Céline ULiege; Bastin, Thierry ULiege

Poster (2018, May 23)

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See detailRadiation pressure on a two-level atom: an exact analytical approach
Podlecki, Lionel ULiege; Glover, Rohan; Martin, John ULiege et al

Poster (2018, May 23)

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See detailRadiation pressure on a two-level atom: an exact analytical approach
Podlecki, Lionel ULiege; Rohan, Glover; Martin, John ULiege et al

Poster (2018, March 07)

Detailed reference viewed: 50 (16 ULiège)
See detailEntanglement robustness of symmetric multiqubit states
Neven, Antoine ULiege; Martin, John ULiege; Bastin, Thierry ULiege

Conference (2018, March)

Detecting the entanglement of a multipartite pure state is a task that can now be addressed using various tools, such as for example, negativity or generalised concurrences. Realising the same task with a ... [more ▼]

Detecting the entanglement of a multipartite pure state is a task that can now be addressed using various tools, such as for example, negativity or generalised concurrences. Realising the same task with a mixed state is however still a challenge today. In a situation where some of the parties of a multipartite entangled pure state are lost, the question arises whether the residual mixed state keeps some of the initial entanglement. In this context, entangled pure states that after partial trace keep some entanglement are said to be robust against party loss and those that lose all entanglement (i.e. become separable) are said to be fragile against party loss. In this talk, we investigate the entanglement robustness against party loss of symmetric multiqubit states. We identify all the fragile states for the loss of 1 qubit and show that these fragile states exhibit a particular symmetry and are all SLOCCequivalent. We also study robustness properties for multiple parties loss and treat exhaustively the case of symmetric states of 4 qubits. [less ▲]

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See detailThe quantum separability problem is a simultaneous hollowisation matrix analysis problem
Neven, Antoine ULiege; Bastin, Thierry ULiege

in Journal of Physics. A, Mathematical and Theoretical (2018), 51

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See detailRadiation pressure on a two-level atom: an exact analytical approach
Podlecki, Lionel ULiege; Glover, Rohan; Martin, John ULiege et al

in Journal of the Optical Society of America. B, Optical Physics (2017), 35(January 2018), 127

Detailed reference viewed: 40 (10 ULiège)
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See detailSimultaneous hollowisation separability criterion in general multipartite systems
Neven, Antoine ULiege; Bastin, Thierry ULiege

Conference (2017, September)

We use the generalized concurrence approach to investigate the general multipartite separability problem. By extending the preconcurrence matrix formalism to arbitrary multipartite systems, we show that ... [more ▼]

We use the generalized concurrence approach to investigate the general multipartite separability problem. By extending the preconcurrence matrix formalism to arbitrary multipartite systems, we show that the separability problem can be formulated equivalently as a pure matrix analysis problem that consists to determine whether a given set of symmetric matrices is simultaneously unitarily congruent to hollow matrices, i.e., to matrices whose main diagonal is only composed of zeroes. [less ▲]

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See detailSeparable states with infinitely many separable decompositions
Neven, Antoine ULiege; Bastin, Thierry ULiege

Poster (2017, June 09)

Despite intense effort in the past decades, developing a general criterion for identifying separable mixed states is still an open problem. In this context, the Positive Partial Transpose (PPT) criterion ... [more ▼]

Despite intense effort in the past decades, developing a general criterion for identifying separable mixed states is still an open problem. In this context, the Positive Partial Transpose (PPT) criterion constituted an important first step towards practical entanglement detection techniques and was later used to investigate the auxiliary problem of finding separable decompositions for separable states. In this poster, we use the rank diminishing method proposed by B. Kraus et al. [PRA 61, 062302 (2000)], that exploits the PPT property to reconstruct separable decompositions, to study the separable decompositions of symmetric PPT states of 3 qubits. We show that any 3-qubit symmetric product states always belong to an optimal separable decomposition of a PPT symmetric 3-qubit state with maximal birank. [less ▲]

Detailed reference viewed: 30 (6 ULiège)
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See detailQuantum fidelity of symmetric multipartite states
Neven, Antoine ULiege; Mathonet, Pierre ULiege; Gühne, Otfried et al

Conference (2017, March)

For two symmetric quantum states one may be interested in maximizing the overlap under local operations applied to one of them. The question arises whether the maximal overlap can be obtained by applying ... [more ▼]

For two symmetric quantum states one may be interested in maximizing the overlap under local operations applied to one of them. The question arises whether the maximal overlap can be obtained by applying the same local operation to each party. We show [1] that for two symmetric multiqubit states and local unitary transformations this is the case; the maximal overlap can be reached by applying the same unitary matrix everywhere. For local invertible operations (stochastic local operations assisted by classical communication equivalence), however, we present counterexamples, demonstrating that considering the same operation everywhere is not enough. [less ▲]

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See detailQuantum fidelity of symmetric multipartite states
Neven, Antoine ULiege; Mathonet, Pierre ULiege; Gühne, Otfried et al

in Physical Review. A (2016), 94

For two symmetric quantum states one may be interested in maximizing the overlap under local operations applied to one of them. The question arises whether the maximal overlap can be obtained by applying ... [more ▼]

For two symmetric quantum states one may be interested in maximizing the overlap under local operations applied to one of them. The question arises whether the maximal overlap can be obtained by applying the same local operation to each party. We show that for two symmetric multiqubit states and local unitary transformations this is the case; the maximal overlap can be reached by applying the same unitary matrix everywhere. For local invertible operations (stochastic local operations assisted by classical communication equivalence), however, we present counterexamples, demonstrating that considering the same operation everywhere is not enough. [less ▲]

Detailed reference viewed: 52 (17 ULiège)
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See detailTowards precision beta-decay measurements with laser-cooled argon-35
Lenaers, Florence ULiege; Glover, Rohan ULiege; Bastin, Thierry ULiege

Poster (2016, October 18)

Laser cooling and trapping techniques enjoy a solid reputation as powerful and elegant providers of well-localized, backing-free sources. Not only does this hold true within the atomic physics and quantum ... [more ▼]

Laser cooling and trapping techniques enjoy a solid reputation as powerful and elegant providers of well-localized, backing-free sources. Not only does this hold true within the atomic physics and quantum optics communities, but also beyond. Most notably, these techniques have recently joined the toolbox of low-energy, high-precision tests of the Standard Model. Our work with argon falls within the subset of nuclear beta decay studies, which have historically played a key role in establishing and testing our understanding of weak-interaction physics. In this framework, precision measurements of the beta asymmetry correlation parameter in the beta decay of Ar-35 have been identified as one promising probe for physics beyond the Standard Model. Our current work focuses on the development of a test magneto-optical trap (MOT) setup for Ar-40 as a preliminary step towards cooling and trapping Ar-35 atoms. In particular, much effort is being put into optimizing the efficiency of our source apparatus, which is crucial to achieving high enough statistics in the final trap. We present the current status of the experimental realization of our setup. Measuring the beta asymmetry correlation parameter requires highly spin-polarized samples. Therefore, in parallel to our experimental work, we are numerically investigating methods for generating, controlling and precisely measuring the degree of spin polarization of a sample of Ar-35 atoms. We also aim at being able to quickly switch between a polarized and a non-polarized sample so as to better understand systematic effects. We report on the progress of our theoretical modeling. [less ▲]

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See detailDevelopment of a hydrogen maser in the TE111 mode
Van Der Beken, Emeline ULiege; Léonard, Daniel; Counet, Arnaud et al

Poster (2016, May 18)

We present the recent progress in the development of a hydrogen maser in the unusual TE111 mode. In contrast to standard hydrogen maser that exploits the TE011 mode, the TE111 mode allows one to design ... [more ▼]

We present the recent progress in the development of a hydrogen maser in the unusual TE111 mode. In contrast to standard hydrogen maser that exploits the TE011 mode, the TE111 mode allows one to design hydrogen masers with significant reduced dimensions which represents a huge benefit for space applications and in particular for the global positioning system. We present in details the different parts of our model : cavity with a thin Teflon sheet, magnetic shielding, temperature control of the maser... [less ▲]

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See detailScattering theory of walking droplets in the presence of obstacles
Dubertrand, Rémy ULiege; Hubert, Maxime ULiege; Schlagheck, Peter ULiege et al

in New Journal of Physics (2016), 18

We aim to describe a droplet bouncing on a vibrating bath using a simple and highly versatile model inspired from quantum mechanics. Close to the Faraday instability, a long-lived surface wave is created ... [more ▼]

We aim to describe a droplet bouncing on a vibrating bath using a simple and highly versatile model inspired from quantum mechanics. Close to the Faraday instability, a long-lived surface wave is created at each bounce, which serves as a pilot wave for the droplet. This leads to so called walking droplets or walkers. Since the seminal experiment by {\it Couder et al} [Phys. Rev. Lett. {\bf 97}, 154101 (2006)] there have been many attempts to accurately reproduce the experimental results. We propose to describe the trajectories of a walker using a Green function approach. The Green function is related to the Helmholtz equation with Neumann boundary conditions on the obstacle(s) and outgoing boundary conditions at infinity. For a single-slit geometry our model is exactly solvable and reproduces some general features observed experimentally. It stands for a promising candidate to account for the presence of arbitrary boundaries in the walker's dynamics. [less ▲]

Detailed reference viewed: 60 (15 ULiège)
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See detailRecent progress in the development of a hydrogen maser in the TE111 mode
Van Der Beken, Emeline ULiege; Léonard, Daniel; Counet, Arnaud et al

Poster (2016, April 06)

We present the recent progress in the development of a hydrogen maser in the unusual TE111 mode. In contrast to standard hydrogen maser that exploits the TE011 mode, the TE111 mode allows one to design ... [more ▼]

We present the recent progress in the development of a hydrogen maser in the unusual TE111 mode. In contrast to standard hydrogen maser that exploits the TE011 mode, the TE111 mode allows one to design hydrogen masers with significant reduced dimensions which represents a huge benefit for space applications and in particular for the global positioning system. We present in details the different parts of our model : cavity with a thin Teflon sheet, magnetic shielding, temperature control of the maser... [less ▲]

Detailed reference viewed: 68 (6 ULiège)
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See detailAnticoherence and entanglement of spin states
Martin, John ULiege; Baguette, Dorian ULiege; Damanet, François ULiege et al

Scientific conference (2016, March 02)

We investigate multiqubit permutation-symmetric states with maxi- mally mixed reduced density matrices in the symmetric subspace [1]. Such states can be viewed as particular spin states, namely anticoher ... [more ▼]

We investigate multiqubit permutation-symmetric states with maxi- mally mixed reduced density matrices in the symmetric subspace [1]. Such states can be viewed as particular spin states, namely anticoher- ent spin states [2]. Using the Majorana representation of spin states in terms of points on the unit sphere [3], we analyze the consequences of degeneracies of the Majorana points and of a point-group symmetry in their arrangement on the existence of anticoherent spin states. We provide different characterizations of anticoherence and establish a link between point symmetries, anticoherence, and SLOCC classes [4]. We consider in detail the case of small numbers of qubits and solve the 4-qubit case completely by identifying and characterizing all 4-qubit anticoherent states. [1] D. Baguette, T. Bastin, and J. Martin, Phys. Rev. A 90, 032314 (2014); O. Giraud et al., Phys. Rev. Lett. 114, 080401 (2015); D. Baguette et al., Phys. Rev. A 92, 052333 (2015). [2] J. Zimba, Electron. J. Theor. Phys. 3, 143 (2006). [3] E. Majorana, Nuovo Cimento 9, 43 (1932). [4] SLOCC classes : Classes of states equivalent through stochastic local operations with classical communication. [less ▲]

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See detailMagneto-optical trapping of iron atoms
Crauwels, Justine ULiege; Huet, Nicolas ULiege; Krins, Stéphanie ULiege et al

in Belgian Physical Society Magazine (2016), 1

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See detailMaximal fidelity between symmetric multiqubit states and entanglement classes
Neven, Antoine ULiege; Mathonet, Pierre ULiege; Gühne, Otfried et al

Poster (2015, September)

We present the results of our research concerning a conjecture about the maximal fidelity between a symmetric (permutation invariant) multiqubit state and the states belonging to a given entanglement ... [more ▼]

We present the results of our research concerning a conjecture about the maximal fidelity between a symmetric (permutation invariant) multiqubit state and the states belonging to a given entanglement class. [less ▲]

Detailed reference viewed: 83 (20 ULiège)
See detailTowards precision β-decay measurements with laser cooled 35Ar
Glover, Rohan ULiege; Lenaers, Florence ULiege; Velten, Philippe et al

Poster (2015, July)

Detailed reference viewed: 51 (10 ULiège)
See detailControl of nuclear sample polarization using optical pumping and radio-frequency methods
Lenaers, Florence ULiege; Glover, Rohan ULiege; Bastin, Thierry ULiege

Conference (2015, May 27)

Laser-cooled and trapped radioactive isotopes are now being used to probe the properties of the weak interaction in nuclear beta decay. In this context, it is essential that one be able to control the ... [more ▼]

Laser-cooled and trapped radioactive isotopes are now being used to probe the properties of the weak interaction in nuclear beta decay. In this context, it is essential that one be able to control the nuclear polarization of the atomic samples. We present two polarization/depolarization schemes for argon-35, whose mirror transition to chlorine-35 is a particularly sensitive candidate for precision measurements in nuclear beta decay. [less ▲]

Detailed reference viewed: 57 (13 ULiège)