Coherent states, phase states, and condensed states

Provost, Jean‐Pierre; Rocca, F.; Vallée, G.

doi:10.1016/0003-4916(75)90170-0

Cited by 22 publications

(14 citation statements)

References 18 publications

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“…As a possible mechanism of periodic emergences of magnetic flux, Sturrock et al (1999), Lou (2000) and Sturrock (2004) suggested that the Rieger and similar Rieger‐type periodicities are related to physical properties of Rossby‐type waves or r modes (Papaloizou & Pringle 1978; Provost, Berthoumieu & Rocca 1981; Wolff & Blizard 1986; Dzhalilov & Staude 2004). The r modes are globally coherent quasi‐toroidal oscillations dominated by Coriolis force which in small‐scale approximation reduces to the Rossby waves (Provost et al 1981). Rossby‐type waves can exist in a fluid on the surface of a rotating sphere and belong to a subset of global tidal waves.…”

Section: Discussionmentioning

confidence: 99%

Intermediate-term periodicities in sunspot areas during solar cycles 22 and 23

Chowdhury

Khan

Ray³

2009

Monthly Notices of the Royal Astronomical Society

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In this paper, the data of sunspot areas recorded at the US Air Force National Oceanic and Atmospheric Administration during solar Cycles 22 and 23 (1986 September 1 to 2007 August 31) have been analysed to investigate the midterm periodicities. Power spectral analysis has been performed separately for the data of the whole disc, and the northern and southern hemispheres of the Sun, which provides evidence for a multitude of quasi‐periodic oscillations. During Cycle 22, in the high‐frequency range, this covers the solar rotation periods, and shows prominent 27–41 d periods in both hemispheres for rising and declining phase of the solar cycle. In the intermediate‐frequency range, we have detected a series of significant quasi‐periodicities of 87–106, 159–175, 194–219, 292–318 and ∼389 d in different phases of Cycle 22. This result shows that well‐known ‘Rieger periodicity’ of 150–160 d was present in sunspot activity even in solar cycle 22 but localized mainly in the southern hemisphere. When Cycle 23 is considered, it is found that a short‐term periodicity having range of 24–45 d occurred in both rising and descending epochs in all hemispheres. On the other hand, in intermediate range, periods of 69–95, 113–133, 160–187, 245–321, 348–406 d and ∼1.3 yr were detected. This analysis provides evidence that the Rieger period reappeared in Cycle 23 but is predominant in the southern part of the Sun. Periods near 1.3 yr, which were reported in the rotation rate at the base of convection zone, have been found in the southern hemisphere only during minimum phase of Cycle 23. When time series of combined solar Cycles 22 and 23 were analysed, intermittent periods in the range of 24–43, 50–73, 86–120, 130–180, 240–270 d and quasi‐annual period of 330–380 d were detected in all the data sets. Possible explanations of these observed periodicities are delivered on the basis of solar r‐mode oscillation.

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Section: Discussionmentioning

confidence: 99%

Intermediate-term periodicities in sunspot areas during solar cycles 22 and 23

Chowdhury

Khan

Ray³

2009

Monthly Notices of the Royal Astronomical Society

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“…As mentioned in the introduction section, the r-modes correspond to the axial modes where the restoring force is the Coriolis force. The r-mode frequency ω c in the corotating frame, to first order in Ω, the rotation frequency of the star is given by [40]…”

Section: R-mode Dampingmentioning

confidence: 99%

Bulk viscosity in a hyperonic star andr-mode instability

2010

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We consider a rotating neutron star with the presence of hyperons in its core, using an equation of state in an effective chiral model within the relativistic mean field approximation. We calculate the hyperonic bulk viscosity coefficient due to nonleptonic weak interactions. By estimating the damping timescales of the dissipative processes, we investigate its role in the suppression of gravitationally driven instabilities in the r-mode. We observe that r-mode instability remains very much significant for hyperon core temperature of around 10 8 K, resulting in a comparatively larger instability window. We find that such instability can reduce the angular velocity of the rapidly rotating star considerably upto ∼ 0.04 ΩK , with ΩK as the Keplerian angular velocity.

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“…However we emphasize that this tensor is meaningless as a metric tensor on a manifold of physical states in ordinary quantum mechanics. Indeed, as long as the phase of a vector state is not observable [8], the physical states are represented by rays of the Hubert space and the two vectors tp(s) and ip'(s)…”

Section: Definition Of a Meaningful Metric Tensormentioning

confidence: 99%

Riemannian structure on manifolds of quantum states

Provost¹,

Vallée²

1980

Commun.Math. Phys.

659

617

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A metric tensor is defined from the underlying Hubert space structure for any submanifold of quantum states. The case where the manifold is generated by the action of a Lie group on a fixed state vector (generalized coherent states manifold hereafter noted G.C.S.M.) is studied in details; the geometrical properties of some wellknown G.C.S.M. are reviewed and an explicit expression for the scalar Riemannian curvature is given in the general case. The physical meaning of such Riemannian structures (which have been recently introduced to describe collective manifolds in nuclear physics) is discussed. It is shown on examples that the distance between nearby states is related to quantum fluctuations; in the particular case of the harmonic oscillator group the condition of zero curvature appears to be identical to that of non dispersion of wave packets.

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Coherent states, phase states, and condensed states

Cited by 22 publications

References 18 publications

Intermediate-term periodicities in sunspot areas during solar cycles 22 and 23

Intermediate-term periodicities in sunspot areas during solar cycles 22 and 23

Bulk viscosity in a hyperonic star andr-mode instability

Riemannian structure on manifolds of quantum states

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