Publications of Thierry Bastin
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See detailRadiation pressure on a multi-level atom: an exact analytical approach
Podlecki, Lionel ULiege; Martin, John ULiege; Bastin, Thierry ULiege

E-print/Working paper (2021)

Nowadays, the mechanical action of laser light is a tool used ubiquitously in cold atom physics, leading to the control of atomic motion with extreme precision. In a recent work, we provided a ... [more ▼]

Nowadays, the mechanical action of laser light is a tool used ubiquitously in cold atom physics, leading to the control of atomic motion with extreme precision. In a recent work, we provided a standardized and exact analytical formalism for computing in the semiclassical regime the radiationforce experienced by a two-level atom interacting with an arbitrary number of plane waves with arbitrary intensities, frequencies, phases, and directions [J. Opt. Soc. Am. B 35, 127-132 (2018)]. Here, we extend this treatment to the multi-level atom case, where degeneracy of the atomic levels is considered and polarization of light enters into play. [less ▲]

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

Poster (2019, January)

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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 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 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 ▲]

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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 ▲]

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See detailMultiqubit symmetric states with maximally mixed one-qubit reductions
Baguette, Dorian ULiege; Bastin, Thierry ULiege; Martin, John ULiege

in Physical Review. A (2014), 90

We present a comprehensive study of maximally entangled symmetric states of arbitrary numbers of qubits in the sense of the maximal mixedness of the one-qubit reduced density operator. A general criterion ... [more ▼]

We present a comprehensive study of maximally entangled symmetric states of arbitrary numbers of qubits in the sense of the maximal mixedness of the one-qubit reduced density operator. A general criterion is provided to easily identify whether given symmetric states are maximally entangled in that respect or not. We show that these maximally entangled symmetric (MES) states are the only symmetric states for which the expectation value of the associated collective spin of the system vanishes, as well as in corollary the dipole moment of the Husimi function. We establish the link between this kind of maximal entanglement, the anticoherence properties of spin states, and the degree of polarization of light fields. We analyze the relationship between the MES states and the classes of states equivalent through stochastic local operations with classical communication (SLOCC). We provide a nonexistence criterion of MES states within SLOCC classes of qubit states and show in particular that the symmetric Dicke state SLOCC classes never contain such MES states, with the only exception of the balanced Dicke state class for even numbers of qubits. The 4-qubit system is analyzed exhaustively and all MES states of this system are identified and characterized. Finally the entanglement content of MES states is analyzed with respect to the geometric and barycentric measures of entanglement, as well as to the generalized N-tangle. We show that the geometric entanglement of MES states is ensured to be larger than or equal to 1/2, but also that MES states are not in general the symmetric states that maximize the investigated entanglement measures. [less ▲]

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See detailMultiqubit symmetric states with a high geometric entanglement
Martin, John ULiege; Giraud, Olivier; Braun, Peter et al

Poster (2011, May 25)

We propose a detailed study of the geometric entanglement properties of pure symmetric N-qubit states, focusing more particularly on the identification of symmetric states with a high geometric ... [more ▼]

We propose a detailed study of the geometric entanglement properties of pure symmetric N-qubit states, focusing more particularly on the identification of symmetric states with a high geometric entanglement and how their entanglement behaves asymptotically for large N. We show that much higher geometric entanglement with improved asymptotical behavior can be obtained in comparison with the highly entangled balanced Dicke states studied previously. We also derive an upper bound for the geometric measure of entanglement of symmetric states. The connection with the quantumness of a state is discussed. [less ▲]

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See detailTrapping particles by optical tweezers
Dujardin, Julien ULiege; Bastin, Thierry ULiege; Vandewalle, Nicolas ULiege

Poster (2010)

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See detailTunable entanglement, antibunching and saturation effects in dipole blockade
Gillet, Jérémie ULiege; Agarwal, G. S.; Bastin, Thierry ULiege

Poster (2010)

Detailed reference viewed: 33 (10 ULiège)
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See detailMultiqubit symmetric states with high geometric entanglement
Martin, John ULiege; Giraud, O.; Braun, P. A. et al

in Physical Review. A (2010), 81(6), 0623471-6

We propose a detailed study of the geometric entanglement properties of pure symmetric N-qubit states, focusing more particularly on the identification of symmetric states with a high geometric ... [more ▼]

We propose a detailed study of the geometric entanglement properties of pure symmetric N-qubit states, focusing more particularly on the identification of symmetric states with a high geometric entanglement and how their entanglement behaves asymptotically for large N. We show that much higher geometric entanglement with improved asymptotical behavior can be obtained in comparison with the highly entangled balanced Dicke states studied previously. We also derive an upper bound for the geometric measure of entanglement of symmetric states. The connection with the quantumness of a state is discussed. [less ▲]

Detailed reference viewed: 47 (6 ULiège)
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See detailCold three-level atom micromaser in the far-detuning regime
Martin, John ULiege; Bastin, Thierry ULiege

in Physical Review. A (2007), 75

We analyze the quantum theory of the two-mode micromaser pumped by cold three-level atoms with a Lambda-configuration under the two-photon resonance condition. We focus more specifically on the large ... [more ▼]

We analyze the quantum theory of the two-mode micromaser pumped by cold three-level atoms with a Lambda-configuration under the two-photon resonance condition. We focus more specifically on the large detuning limit where the detuning between the two cavity mode frequencies and the two atomic transition frequencies is large in comparison with the atom-cavity coupling constants. We show that this regime can mimic a virtual two-level atom micromaser without spontaneous emission where the cavity acts for the atoms as a potential barrier or a potential well (depending on the sign of the detuning) and a zero potential but no more both as a potential barrier and a potential well as it is the case for the usual cold two-level atom micromaser [M. O. Scully, G. M. Meyer, and H. Walther, Phys. Rev. Lett. 76, 4144 (1996)]. This introduces interesting options for engineering the interaction between the cold atoms and the cavity. The elimination of the spontaneous emission solves a major issue of the conventional cold two-level atom micromaser as the transit time of cold atoms inside and in the vicinity of the cavity is usually much larger than the atomic level lifetimes. It is also shown that the cold atom regime is very sensitive to the sign of the detuning (in contrast to the hot atom regime) and that, according to this sign, the cavity may speed up or slow down the incident three-level atoms after their interaction with the field. [less ▲]

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See detailQuantum Imaging with Incoherent Photons
Thiel, C.; Bastin, Thierry ULiege; Martin, John ULiege et al

in Physical Review Letters (2007), 99

We propose a technique to obtain subwavelength resolution in quantum imaging with potentially 100% contrast using incoherent light. Our method requires neither path-entangled number states nor multiphoton ... [more ▼]

We propose a technique to obtain subwavelength resolution in quantum imaging with potentially 100% contrast using incoherent light. Our method requires neither path-entangled number states nor multiphoton absorption. The scheme makes use of N photons spontaneously emitted by N atoms and registered by N detectors. It is shown that for coincident detection at particular detector positions a resolution of lambda/N can be achieved. [less ▲]

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See detailReply to "Comment on 'Detuning effects in the one-photon mazer' "
Bastin, Thierry ULiege; Martin, John ULiege

in Physical Review. A (2004), 70

We refute in this Reply the criticisms made by Abdel-Aty. We show that none of them are founded and we demonstrate very explicitly what is wrong with the arguments developed by this author.

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See detailDetuning effects on the mazer
Martin, John ULiege; Bastin, Thierry ULiege

in Physicalia Magazine (2003), 25

A short review of the theoretical studies of the cold atom micromaser (mazer) is presented. Existing models are then improved by considering more general working conditions. Especially, the mazer physics ... [more ▼]

A short review of the theoretical studies of the cold atom micromaser (mazer) is presented. Existing models are then improved by considering more general working conditions. Especially, the mazer physics is investigated in the situation where a detuning between the cavity mode and the atomic transition frequency is present. Interesting new effects are pointed out. Especially, it is shown that the cavity may slow down or speed up the atoms according to the sign of the detuning and that the induced emission process may be completely blocked by use of a positive detuning. The transmission probability of ultracold atoms through a micromaser is also studied and we generalize previous results established in the resonant case. In particular, it is shown that the velocity selection of cold atoms passing through the micromaser can be very easily tuned and enhanced using a nonresonant field inside the cavity. [less ▲]

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See detailDetuning effects in the one-photon mazer
Bastin, Thierry ULiege; Martin, John ULiege

in Physical Review. A (2003), 67

The quantum theory of the mazer in the nonresonant case (a detuning between the cavity mode and the atomic transition frequencies is present) is described. The generalization from the resonant case is far ... [more ▼]

The quantum theory of the mazer in the nonresonant case (a detuning between the cavity mode and the atomic transition frequencies is present) is described. The generalization from the resonant case is far from being direct. Interesting effects of the mazer physics are pointed out. In particular, it is shown that the cavity may slow down or speed up the atoms according to the sign of the detuning and that the induced emission process may be completely blocked by use of a positive detuning. It is also shown that the detuning adds a potential step effect not present at resonance and that the use of positive detunings defines a well-controlled cooling mechanism. In the special case of a mesa cavity mode function, generalized expressions for the reflection and transmission coefficients have been obtained. The general properties of the induced emission probability are finally discussed in the hot, intermediate, and cold atom regimes. Comparison with the resonant case is given. [less ▲]

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