31.20.+t Quantum state transport in quantum chains and arrays

Energy transport between two integrable spin chains

Date: 
2016-05-13
Author(s): 

Alberto Biella, Andrea De Luca, Jacopo Viti, Davide Rossini, Leonardo Mazza, and Rosario Fazio

Reference: 

Phys. Rev. B 93, 205121 (2016)

We study the energy transport in a system of two half-infinite XXZ chains initially kept separated at different temperatures, and later connected and let free to evolve unitarily. By changing independently the parameters of the two halves, we highlight, through bosonization and time-dependent matrix-product-state simulations, the different contributions of low-lying bosonic modes and of fermionic quasiparticles to the energy transport. In the simulations we also observe that the energy current reaches a finite value which only slowly decays to zero.

Photon transport in a dissipative chain of nonlinear cavities

Date: 
2015-05-12
Author(s): 

Alberto Biella, Leonardo Mazza, Iacopo Carusotto, Davide Rossini, and Rosario Fazio

Reference: 

Phys. Rev. A 91, 053815 (2015)

By means of numerical simulations and the input-output formalism, we study photon transport through a chain of coupled nonlinear optical cavities subject to uniform dissipation. Photons are injected from one end of the chain by means of a coherent source. The propagation through the array of cavities is sensitive to the interplay between the photon hopping strength and the local nonlinearity in each cavity. We characterize photon transport by studying the populations and the photon correlations as a function of the cavity position.

Realistic and verifiable coherent control of excitonic states in a light harvesting complex

Date: 
2013-07-18 - 2014-01-20
Author(s): 

Stephan Hoyer, Filippo Caruso, Simone Montangero, Mohan Sarovar, Tommaso Calarco, Martin B. Plenio and K. Birgitta Whaley

Reference: 

New Journal of Physics 16, 045007 (2014)

We explore the feasibility of coherent control of excitonic dynamics in light harvesting complexes, analyzing the limits imposed by the open nature of these quantum systems. We establish feasible targets for phase and phase/amplitude control of the electronically excited state populations in the Fenna-Mathews-Olson (FMO) complex and analyze the robustness of this control with respect to orientational and energetic disorder, as well as decoherence arising from coupling to the protein environment.

Spontaneous nucleation of structural defects in inhomogeneous ion chains

Date: 
2010-06-30
Reference: 

A. del Campo, G. De Chiara, G. Morigi, M. B. Plenio and A. Retzker

Structural defects in ion crystals can be formed during a linear quench of the transverse trapping frequency across the mechanical instability from a linear chain to the zigzag structure. The density of defects after the sweep can be conveniently described by the Kibble-Zurek mechanism. In particular, the number of kinks in the zigzag ordering can be derived from a time-dependent Ginzburg-Landau equation for the order parameter, here the zigzag transverse size, under the assumption that the ions are continuously laser cooled.

Quantum zigzag transition in interacting atom chains

Date: 
2010-08-13
Reference: 

E. Shimshoni, G. Morigi and S. Fishman
http://arxiv.org/abs/1008.2326

A string of trapped interacting ions at zero temperature ($T=0$) exhibits a structural phase transition to a zigzag structure, tuned by reducing the transverse trap potential or increasing the particle density. The transition is driven by transverse, short wavelength vibrational modes. We propose a quantum field--theoretical description of this transition by the one dimensional Ising model in a transverse field.

Spin-Dependent Transport through Quantum-Dot Aharonov-Bohm Interferometers

Date: 
2010-10-29
Author(s): 

B. Hiltscher, M. Governale, and J. König

Reference: 

Phys. Rev. B 82, 165452 (2010)

We study the influence of spin polarization on the degree of coherence of electron transport through interacting quantum dots. To this end, we identify transport regimes in which the degree of coherence can be related to the visibility of the Aharonov-Bohm oscillations in the current through a quantum-dot Aharonov-Bohm interferometer with one normal and one ferromagnetic lead. For these regimes, we calculate the visibility and, thus, the degree of coherence, as a function of the degree of spin polarization of the ferromagnetic lead.

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