Abstract:The evolution of a surface excitation in a two dimentional model is analyzed. I) It starts quadratically up to a spreading time t S. 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 t R a survival collapse becomes possible, bringing the survival probability down by several orders of magnitude. We identify this str… Show more
“…When they have imaginary parts, only those with negative ones represent a decaying response to an initial condition. These imaginary parts are precisely the exponential decay rate in the self-consistent Fermi golden rule [61]. When the four poles are real, the physical ones should approach to the isolated system poles (shown in Fig.…”
Section: Analytic Solutionmentioning
confidence: 97%
“…In this case the environment size is taken large enough so the mesoscopic echoes do not show up at the times of interest [61]. The evaluation of P AA (t) allows us to univocally identify the localized states and the different decay laws of the other regimes.…”
Section: Parametric Regionsmentioning
confidence: 99%
“…Under this condition, P AA (t) decays exponentially and without oscillations until the survival collapse time [61]. At this moment the return amplitude from the environment starts to be comparable with the pure survival amplitude interfering destructively [see Fig.…”
Section: A Region I: Collapsed Resonances (Overdamped Decay)mentioning
confidence: 99%
“…If we set V 0 = 1V we arrive to the case already treated in Ref. [61] where it is analyzed the decay of a surface spin excitation when it interacts with a spin chain. A similar dynamics was recently predicted for a quasiparticle excitation at adsorbates in a surface band [62].…”
Section: A Region I: Collapsed Resonances (Overdamped Decay)mentioning
We discuss how the bath's memory affects the dynamics of a swap gate. We present an exactly solvable model that shows various dynamical transitions when treated beyond the Fermi Golden Rule. By moving continuously a single parameter, the unperturbed Rabi frequency, we sweep through different analytic properties of the density of states: (I) collapsed resonances that split at an exceptional point in (II) two resolved resonances ; (III) out-of-band resonances; (IV) virtual states; and (V) pure point spectrum. We associate them with distinctive dynamical regimes: overdamped, damped oscillations, environment controlled quantum diffusion, anomalous diffusion and localized dynamics respectively. The frequency of the swap gate depends differently on the unperturbed Rabi frequency. In region I there is no oscillation at all, while in the regions III and IV the oscillation frequency is particularly stable because it is determined by the environment's band width. The anomalous diffusion could be used as a signature for the presence of the elusive virtual states.
“…When they have imaginary parts, only those with negative ones represent a decaying response to an initial condition. These imaginary parts are precisely the exponential decay rate in the self-consistent Fermi golden rule [61]. When the four poles are real, the physical ones should approach to the isolated system poles (shown in Fig.…”
Section: Analytic Solutionmentioning
confidence: 97%
“…In this case the environment size is taken large enough so the mesoscopic echoes do not show up at the times of interest [61]. The evaluation of P AA (t) allows us to univocally identify the localized states and the different decay laws of the other regimes.…”
Section: Parametric Regionsmentioning
confidence: 99%
“…Under this condition, P AA (t) decays exponentially and without oscillations until the survival collapse time [61]. At this moment the return amplitude from the environment starts to be comparable with the pure survival amplitude interfering destructively [see Fig.…”
Section: A Region I: Collapsed Resonances (Overdamped Decay)mentioning
confidence: 99%
“…If we set V 0 = 1V we arrive to the case already treated in Ref. [61] where it is analyzed the decay of a surface spin excitation when it interacts with a spin chain. A similar dynamics was recently predicted for a quasiparticle excitation at adsorbates in a surface band [62].…”
Section: A Region I: Collapsed Resonances (Overdamped Decay)mentioning
We discuss how the bath's memory affects the dynamics of a swap gate. We present an exactly solvable model that shows various dynamical transitions when treated beyond the Fermi Golden Rule. By moving continuously a single parameter, the unperturbed Rabi frequency, we sweep through different analytic properties of the density of states: (I) collapsed resonances that split at an exceptional point in (II) two resolved resonances ; (III) out-of-band resonances; (IV) virtual states; and (V) pure point spectrum. We associate them with distinctive dynamical regimes: overdamped, damped oscillations, environment controlled quantum diffusion, anomalous diffusion and localized dynamics respectively. The frequency of the swap gate depends differently on the unperturbed Rabi frequency. In region I there is no oscillation at all, while in the regions III and IV the oscillation frequency is particularly stable because it is determined by the environment's band width. The anomalous diffusion could be used as a signature for the presence of the elusive virtual states.
“…However, the characteristic rate of a flip-flop due to the weak cross-chain couplings should be estimated invoking the Fermi golden rule that yields [36] 1…”
Section: Dynamical Enhancement Of the One-dimensionality By The mentioning
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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