References of "Bastin, Thierry"
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See detailTowards precision β-decay measurements with laser cooled 35Ar
Glover, Rohan ULg; Lenaers, Florence ULg; Velten, Philippe et al

Poster (2015, July)

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See detailControl of nuclear sample polarization using optical pumping and radio-frequency methods
Lenaers, Florence ULg; Glover, Rohan ULg; Bastin, Thierry ULg

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 ▲]

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See detailFirst experimental realization of an Iron Magneto-Optical Trap
Bastin, Thierry ULg; Crauwels, Justine ULg; Huet, Nicolas ULg et al

Conference (2015, May 13)

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See detailAnticoherence of multiqubit symmetric states
Baguette, Dorian ULg; Bastin, Thierry ULg; Martin, John ULg

Conference (2015, May 13)

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See detailInvestigation on a hydrogen maser cavity in the TE111 mode : first results
Van Der Beken, Emeline ULg; Léonard, Daniel; Counet, Arnaud et al

Poster (2015, May 13)

Results of our preliminary investigation on a hydrogen maser cavity in the unusual TE111 mode are presented. Hydrogen masers use the transition at 1420.405MHz between the two hyperfine levels F = 0 and F ... [more ▼]

Results of our preliminary investigation on a hydrogen maser cavity in the unusual TE111 mode are presented. Hydrogen masers use the transition at 1420.405MHz between the two hyperfine levels F = 0 and F = 1 of the 1s1/2 ground state of the hydrogen atom. 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. In view of a future development of a hydrogen maser in the TE111 mode we performed a thorough analysis of the maser physics for this mode. Different simulations carried out are compared with first measurement results obtained for such a cavity. [less ▲]

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

Poster (2015, May 13)

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See detailPreliminary results for a hydrogen maser cavity in the TE111 mode
Van Der Beken, Emeline ULg; Léonard, Daniel; Counet, Arnaud et al

Poster (2015, April 13)

An analysis of a hydrogen maser working with an unusual TE111 mode is presented. Different simulations have been carried out and are compared with preliminary results obtained for such a maser. In ... [more ▼]

An analysis of a hydrogen maser working with an unusual TE111 mode is presented. Different simulations have been carried out and are compared with preliminary results obtained for such a maser. 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. [less ▲]

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See detailTensor Representation of Spin States
Giraud, Olivier; Braun, Daniel; Baguette, Dorian ULg et al

in Physical Review Letters (2015), 114

We propose a generalization of the Bloch sphere representation for arbitrary spin states. It provides a compact and elegant representation of spin density matrices in terms of tensors that share the most ... [more ▼]

We propose a generalization of the Bloch sphere representation for arbitrary spin states. It provides a compact and elegant representation of spin density matrices in terms of tensors that share the most important properties of Bloch vectors. Our representation, based on covariant matrices introduced by Weinberg in the context of quantum field theory, allows for a simple parametrization of coherent spin states, and a straightforward transformation of density matrices under local unitary and partial tracing operations. It enables us to provide a criterion for anticoherence, relevant in a broader context such as quantum polarization of light. [less ▲]

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See detailOperational entanglement families of symmetric mixed N-qubit states
Bastin, Thierry ULg; Mathonet, Pierre ULg; Solano, Enrique

in Physical Review A (2015), 91

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See detailOptical collimation of an atomic beam using a white light molasses
Glover, Rohan ULg; Bastin, Thierry ULg

in Journal of the Optical Society of America. B, Optical Physics (2015), 32(5), 1-10

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

Poster (2014, November 18)

We present a comprehensive study on the remarquable properties shared by maximally entangled symmetric states of arbitrary numbers of qubits in the sense of the maximal mixedness of the one-qubit reduced ... [more ▼]

We present a comprehensive study on the remarquable properties shared by maximally entangled symmetric states of arbitrary numbers of qubits in the sense of the maximal mixedness of the one-qubit reduced density operator. Such states are of great interest in quantum information as they maximize several measures of entanglement, such as Meyer-Wallach entropy [1] and any entanglement monotone based on linear homogenous positive functions of pure state within their SLOCC classes of states [2, 3]. When they exist, they are unique up to local unitaries within their SLOCC classes [3, 4]. They play a specific role in the determination of the local unitary equivalence of multiqubit states [5]. Moreover, they are maximally fragile (in the sense that they are the states which are the most sensitive to noise) and have therefore been proposed as ideal candidates for ultrasensitive sensors [6]. They appear in the litterature under various names : maximally entangled states [6], 1-uniform states [7], normal forms [3, 4] and nongeneric states [5]. We present a general criterion to easily identify whether given symmetric states are maximally entangled or not [9]. We show that these maximally entangled symmetric (MES) states are the only symmetric states for which the expectation value of the associated collective spin S of the system vanishes, which coincides with the definition of anticoherence to order one of spin states. This definition also coincides with the cancellation of the dipole moment of the Husimi function of the state. We then generalize these properties and show that a state is anticoherent to order t, <(S.n)^k> is independent of n for k = 1, . . . , t, where n is a unit vector, iff it has maximally mixed t-qubit reductions or iff all moments up to order 2t of its Husimi function vanish. We also establish the equivalence between anticoherent states to order t and unpolarized light states to order t [8], thereby encompassing various state characterizations under the same banner [9, 10]. We provide a nonexistence criterion allowing us to know immediately whether SLOCC classes of symmetric states can contain MES states or not. We 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. We analyze the 4-qubit system exhaustively and identify and characterize all MES states of this system as well as the only 4-qubit state anticoherent to order 2. Finally, we analyze the entanglement content of MES states with respect to the geometric [11] and barycentric [12] measures of entanglement. [1] D. A. Meyer and N. R. Wallach, J. Math. Phys. 43, 4273 (2002). [2] Classes of states equivalent through stochastic local operations with classical communication. [3] F. Verstraete, J. Dehaene, and B. De Moor, Phys. Rev. A 68, 012103 (2003). [4] G. Gour and N. Wallach, N. J. Phys. 13, 073013 (2011). [5] B. Kraus, Phys. Rev. Lett. 104, 020504 (2010). [6] N. Gisin and H. Bechmann-Pasquinucci, Phys. Lett. A 246, 1 (1998). [7] A. J. Scott, Phys. Rev. A 69, 052330 (2004). [8] L. L. Sánchez-Soto, A. B. Klimov, P. de la Hoz, and G. Leuchs J. Phys. B : At. Mol. Opt. Phys. 46, 104011 (2013). [9] D. Baguette, T. Bastin, and J. Martin, Phys. Rev. A 90, 032314 (2014). [10] O. Giraud, D. Braun, D. Baguette, T. Bastin, and J. Martin, arXiv :1409.1106. [11] T.-C. Wei and P. M. Goldbart, Phys. Rev. A 68, 042307 (2003). [12] W. Ganczarek, M. Kus, and K. Zyczkowski, Phys. Rev. A 85, 032314 (2012). [less ▲]

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

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 detailImproving CKM Unitary Limits via Low-Energy Nuclear Physics
Finlay, Paul; Ball, G.; Bastin, Thierry ULg et al

Conference (2014, August)

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See detailSymmetric N-qubit anticoherent states
Baguette, Dorian ULg; Bastin, Thierry ULg; Martin, John ULg

Poster (2014, June 23)

Entanglement is among the key features of quantum mechanics. In the last decade, a lot of efforts has been made to quantify the amount of entanglement of various multipartite states, either pure or mixed ... [more ▼]

Entanglement is among the key features of quantum mechanics. In the last decade, a lot of efforts has been made to quantify the amount of entanglement of various multipartite states, either pure or mixed. In particular, the search for maximally entangled states (states maximizing certain measures of entanglement) has focused a great deal of attention, see e.g. Refs. [1–4]. In this work, we present a comprehensive study of maximally entangled symmetric N-qubit states with respect to the definition of Gisin [1]. According to this definition, a state is maximally entangled if all its one-qubit reduced density matrices are maximally mixed. These states maximize various entanglement measures, such as von Neumann and Meyer-Wallach entropies [5]. They are unique up to local unitaries within the class of states interconvertible under stochastic local operations and classical communication (SLOCC) [3]. Besides, they are conjectured to be maximally entangled with respect to the Negative Partial Transpose measure of entanglement [6]. As appreciated by B. Kraus, they play an important role in the determination of the local unitary equivalence of multiqubit states [7]. Moreover, they are maximally fragile (in the sense that they are the states which are the most sensitive to noise) and therefore have been proposed as ideal candidates for ultrasensitive sensors [1]. We provide general conditions for a symmetric state with an arbitrary number of qubits to be maximally entangled and identify families of SLOCC classes which do not contain any such states. We also compute various measure of entanglement associated with those states in order to characterize them further and find all maximally entangled states up to 4 qubits. We finally prove that maximally entangled states coincide with anticoherent states of order 1. According to the definition of Ref. [8], a symmetric state of N qubits is anticoherent to order t iff 〈(S·n)k〉 is independent of n for k = 1, . . . , t where n is a tridimensional unit vector and S is the collective spin operator associated to the N-qubit system. [1] N. Gisin, H. Bechmann-Pasquinucci, Phys. Lett. A 246 (1998). [2] A. Higuchi, A. Sudbery, Phys. Lett. A, 272, 213 (2000). [3] F. Verstraete, J. Dehaene, B. De Moor, Phys. Rev. A 68, 012103 (2003). [4] J. Martin, O. Giraud, P. A. Braun, D. Braun and T. Bastin, Phys. Rev. A 81, 062347 (2010). [5] D. A. Meyer, N. R. Wallach, J. Math. Phys. 43, 4273 (2002). [6] I. D. K. Brown, S. Stepney, A. Sudbery, and S. L. Braunstein, J. Phys. A 38, 1119 (2005). [7] B. Kraus, Phys. Rev. Lett. 104, 020504 (2010). [8] J. Zimba, EJTP 3, 10 (2006). [less ▲]

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See detailOn the Identication of Symmetric N-qubit Maximally Entangled States
Baguette, Dorian ULg; Bastin, Thierry ULg; Martin, John ULg

Poster (2014, March 11)

Maximally entangled states can serve as a useful resource in many different contexts. It is therefore important to identify those states. Here we are interested in the identification of maximally ... [more ▼]

Maximally entangled states can serve as a useful resource in many different contexts. It is therefore important to identify those states. Here we are interested in the identification of maximally entangled states in the symmetric subspace of an N-qubit system. By maximally entangled states, we refer to symmetric states characterized by a one qubit reduced density matrix proportional to the identity. These states maximise various entanglement measures [1] such as von Neumann and Meyer-Wallach entropy and are unique up to LU in their SLOCC class [2]. We identify and characterize all maximally entangled symmetric states up to 4 qubits. We provide general conditions for a symmetric state with an arbitrary number of qubits to be maximally entangled and identify families of SLOCC classes which do not contain any maximally entangled states. [1] F. Verstraete, J. Dehaene, B. De Moor, Phys. Rev. A 68, 012103 (2003). [2] G. Gour, N. Wallach, N. J. Phys. 13, 073013 (2011) [less ▲]

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See detailNonlinear Schrödinger wave equation with linear quantum behavior
Richardson, Christopher ULg; Schlagheck, Peter ULg; Martin, John ULg et al

in Physical Review A (2014), 89

We show that a nonlinear Schroedinger wave equation can reproduce all the features of linear quantum mechanics. This nonlinear wave equation is obtained by exploring, in a uniform language, the transition ... [more ▼]

We show that a nonlinear Schroedinger wave equation can reproduce all the features of linear quantum mechanics. This nonlinear wave equation is obtained by exploring, in a uniform language, the transition from fully classical theory governed by a nonlinear classical wave equation to quantum theory. The classical wave equation includes a nonlinear classicality enforcing potential which when eliminated transforms the wave equation into the linear Schro ̈dinger equation. We show that it is not necessary to completely cancel this nonlinearity to recover the linear behavior of quantum mechanics. Scaling the classicality enforcing potential is sufficient to have quantumlike features appear and is equivalent to scaling Planck’s constant. [less ▲]

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See detailTowards magneto-optical trapping of iron atoms
Crauwels, Justine ULg; Huet, Nicolas ULg; Krins, Stéphanie ULg et al

Poster (2013, September)

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See detailHyperfine-structure splitting of the 716 nm R(90)3–10 molecular iodine transition
Huet, Nicolas ULg; Krins, Stéphanie ULg; Dubé, Pierre et al

in Journal of the Optical Society of America. B, Optical Physics (2013), 30

We report on the hyperfine-structure splitting of the 716 nm R 90 3–10 molecular iodine transition. We show that this particular iodine line provides a very useful frequency reference in the context of a ... [more ▼]

We report on the hyperfine-structure splitting of the 716 nm R 90 3–10 molecular iodine transition. We show that this particular iodine line provides a very useful frequency reference in the context of a laser cooling experiment of iron atoms, an atomic species that has so far never been laser cooled and trapped to our knowledge. We provide experimental values for the hyperfine constants ΔeQq and ΔC of the investigated iodine transition. Dispersive signals of this transition are also presented and used to lock the frequency of a Ti:sapphire laser. The reported stabilization performance is fully compatible with the requirements of a laser cooling experiment of iron atoms. [less ▲]

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See detailLaser Cooling of Iron Atoms
Huet, Nicolas ULg; Krins, Stéphanie ULg; Bastin, Thierry ULg

Poster (2013, March 21)

We report on the first laser cooling of Iron atoms. Our laser cooling setup makes use of 2 UV laser radiations sent colinearly in a 0.8 m Zeeman slower. One laser is meant for optical pumping of the Iron ... [more ▼]

We report on the first laser cooling of Iron atoms. Our laser cooling setup makes use of 2 UV laser radiations sent colinearly in a 0.8 m Zeeman slower. One laser is meant for optical pumping of the Iron atoms from the ground state to the lowest energy metastable state. The second laser cools down the atoms using a quasi-perfect closed transition from the optically pumped metastable state. The velocity distribution at the exit of the Zeeman slower is obtained from a probe laser crossing the atomic beam at an angle of 50 degrees. The fluorescence light is detected using a photomultiplier tube coupled with a boxcar analyzer. The Iron atom beam is produced with a commercial effusion cell working at around 1600°C. Our laser radiations are stabilized using standard saturated-absorption signals in both an Iron hollow cathode absorption cell and an Iodine cell. [less ▲]

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See detailLaser Cooling of Iron Atoms
Bastin, Thierry ULg; Huet, Nicolas ULg; Krins, Stéphanie ULg

Conference (2013, March 18)

We report on the first laser cooling of Iron atoms. Our laser cooling setup makes use of 2 UV laser radiation sent colinearly in a 0.8~m Zeeman slower. One laser is meant for optical pumping of the Iron ... [more ▼]

We report on the first laser cooling of Iron atoms. Our laser cooling setup makes use of 2 UV laser radiation sent colinearly in a 0.8~m Zeeman slower. One laser is meant for optical pumping of the Iron atoms from the ground state to the lowest energy metastable state. The second laser cools down the atoms using a quasi-perfect closed transition from the optical pumped metastable state. The velocity distribution at the exit of the Zeeman slower is obtained from a probe laser crossing the atom beam at an angle of 50 degrees. The fluorescence light is detected using a photomultiplier tube coupled with a boxcar analyzer. The Iron atom beam is produced with a commercial effusion cell working at around 1950 K. Our laser radiations are stabilized using standard saturated-absorption signals in both an Iron hollow cathode absorption cell and an Iodine cell. We will present our experimental setup, as well as the first evidences of cooled down Iron atoms at the exit of the Zeeman slower. [less ▲]

Detailed reference viewed: 66 (9 ULg)