Spin projection chromatography

Danieli, Ernesto; Pastawski, Horacio M.; Levstein, Patricia R.

doi:10.1016/j.cplett.2003.11.104

Cited by 16 publications

(25 citation statements)

References 31 publications

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“…1, the dynamics of an initial state ρ (0) under H DQ is reduced to the dynamics of ρ (0) under H XY which, in turn, maps to a non-interacting fermion system [32,33,34]. The dynamics of this fermionic system has a closed analytical solution when the interaction is homogeneous,…”

Section: Figmentioning

confidence: 99%

Effective one-body dynamics in multiple-quantum NMR experiments

et al. 2009

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A suitable NMR experiment in a one-dimensional dipolar coupled spin system allows one to reduce the natural many-body dynamics into effective one-body dynamics. We verify this in a polycrystalline sample of hydroxyapatite (HAp) by monitoring the excitation of NMR many-body superposition states: the multiple-quantum coherences. The observed effective one-dimensionality of HAp relies on the quasi one-dimensional structure of the dipolar coupled network that, as we show here, is dynamically enhanced by the quantum Zeno effect. Decoherence is also probed through a Loschmidt echo experiment, where the time reversal is implemented on the double-quantum Hamiltonian, HDQ ∝ IWe contrast the decoherence of adamantane, a standard threedimensional system, with that of HAp. While the first shows an abrupt Fermi-type decay, HAp presents a smooth exponential law.

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Section: Figmentioning

confidence: 99%

Effective one-body dynamics in multiple-quantum NMR experiments

et al. 2009

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“…Considering that we are in the high temperature regime, i.e., k B T is much higher than any energy scale of the system, this enables us to re-write Eq. (1) as [21] …”

Section: The Keldysh Formalism For Open Systemsmentioning

confidence: 99%

“…While this novel situation is presented here for the first time, the formalism already inspired original experimental and theoretical developments in coherent spin dynamics involving quantum interferences in the time domain. In particular, it was used to develop the notion of polarization waves leading to mesoscopic echoes [17,18], to establish the influence of chaos on time reversal (Loschmidt echoes) [19,20] and to establish the possibility of a spin projection chromatography [21]. A rough account of many-body decoherence enabled the interpretation of anomalies in spin "diffusion" experiments as a manifestation of the quantum Zeno effect [22].…”

Section: Introductionmentioning

confidence: 99%

Quantum dynamics under coherent and incoherent effects of a spin bath in the Keldysh formalism: application to a spin swapping operation

Danieli

Pastawski

Álvarez

2005

Chemical Physics Letters

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We develop the Keldysh formalism for the polarization dynamics of an open spin system. We apply it to the swapping between two qubit states in a model describing an NMR cross-polarization experiment. The environment is a set of interacting spins. For fast fluctuations in the environment, the analytical solution shows effects missed by the secular approximation of the Quantum Master Equation for the density matrix: a frequency decrease depending on the system-environment escape rate and the quantum quadratic short time behavior. Considering full memory of the bath correlations yields a progressive change of the swapping frequency.

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“…Specifically, our model describes a linear chain of nuclear spins interacting under an XY (planar) interaction. In this situation, the evolution of a local spin excitation reduces to the dynamics of a localized density excitation in a system of non-interacting fermions [17,18,19]. This excitation decays into a well resolved wave packet propagating along the spin chain.…”

Section: Introductionmentioning

confidence: 99%

Non-Markovian decay beyond the Fermi Golden Rule: Survival collapse of the polarization in spin chains

Fiori

Pastawski

2006

Chemical Physics Letters

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The decay of a local spin excitation in an inhomogeneous spin chain is evaluated exactly: I) It starts quadratically up to a spreading time tS. II) It follows an exponential behavior governed by a self-consistent Fermi Golden Rule. III) At longer times, the exponential is overrun by an inverse power law describing return processes governed by quantum diffusion. At this last transition time tR a survival collapse becomes possible, bringing the polarization down by several orders of magnitude. We identify this strongly destructive interference as an antiresonance in the time domain. These general phenomena are suitable for observation through an NMR experiment.

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Spin projection chromatography

Cited by 16 publications

References 31 publications

Effective one-body dynamics in multiple-quantum NMR experiments

Effective one-body dynamics in multiple-quantum NMR experiments

Quantum dynamics under coherent and incoherent effects of a spin bath in the Keldysh formalism: application to a spin swapping operation

Non-Markovian decay beyond the Fermi Golden Rule: Survival collapse of the polarization in spin chains

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