0000000000218449

AUTHOR

Jiannis K. Pachos

0000-0002-9775-4436

showing 4 related works from this author

Geometric phases and criticality in spin systems

2006

A general formalism of the relation between geometric phases produced by circularly evolving interacting spin systems and their criticality behavior is presented. This opens up the way for the use of geometric phases as a tool to study regions of criticality without having to undergo a quantum phase transition. As a concrete example a spin-1/2 chain with XY interactions is presented and the corresponding geometric phases are analyzed. The generalization of these results to the case of an arbitrary spin system provides an explanation for the existence of such a relation.

PhysicsQuantum phase transitionQuantum PhysicsXY modelBerry phaseGeneral MathematicsGeneral EngineeringSpin systemGeneral Physics and AstronomyFOS: Physical sciencescritical phenomenaFormalism (philosophy of mathematics)Theoretical physicsCriticalityQuantum Physics (quant-ph)
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Journeys from quantum optics to quantum technology

2017

Sir Peter Knight is a pioneer in quantum optics which has now grown to an important branch of modern physics to study the foundations and applications of quantum physics. He is leading an effort to develop new technologies from quantum mechanics. In this collection of essays, we recall the time we were working with him as a postdoc or a PhD student and look at how the time with him has influenced our research.

EngineeringTechnologyAtomic and Molecular Physics and OpticEmerging technologiesQuantum technologiesTRAPPED IONQuantum physicsSINGLE-ATOM0205 Optical PhysicsPhysics - History and Philosophy of PhysicsNONCLASSICAL MOTIONAL STATESFOS: Physical sciences01 natural sciences010305 fluids & plasmasTheoretical physicsQC350Engineering0202 Atomic Molecular Nuclear Particle And Plasma Physics0103 physical sciencesPERIODIC LEVEL-CROSSINGSStatistical and Nonlinear Physics; Electronic Optical and Magnetic Materials; Atomic and Molecular Physics and Optics; Electrical and Electronic EngineeringHistory and Philosophy of Physics (physics.hist-ph)ULTRAFAST MOLECULAR-DYNAMICSElectrical and Electronic Engineering010306 general physicsQCQuantum opticsScience & Technologybusiness.industryElectronic Optical and Magnetic MaterialModern physics0906 Electrical And Electronic EngineeringINDUCED ELECTRON-DIFFRACTIONStatistical and Nonlinear PhysicsEngineering Electrical & ElectronicOpticsModern physicsAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic MaterialsQuantum technologyQuantum theoryINDUCED CONTINUUM STRUCTUREHIGH-HARMONIC-GENERATIONENTANGLED COHERENT STATESQuantum Physics (quant-ph)businessBAND SQUEEZED VACUUMStatistical and Nonlinear Physic
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Geometric phases and criticality in spin chain systems

2005

A relation between geometric phases and criticality of spin chains is established. As a result, we show how geometric phases can be exploited as a tool to detect regions of criticality without having to undergo a quantum phase transition. We analytically evaluate the geometric phase that correspond to the ground and excited states of the anisotropic XY model in the presence of a transverse magnetic field when the direction of the anisotropy is adiabatically rotated. Ultra-cold atoms in optical lattices are presented as a possible physical realization.

Quantum phase transitionPhysicsQuantum PhysicsCondensed matter physicsCondensed Matter - Mesoscale and Nanoscale PhysicsPhase (waves)General Physics and AstronomyFOS: Physical sciencesQuantum phase transitionClassical XY modelSpin-chain systemsGeometric phaseCriticalityUltracold atomQuantum mechanicsMesoscale and Nanoscale Physics (cond-mat.mes-hall)AnisotropyQuantum Physics (quant-ph)Spin-½
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Spectrum of the non-abelian phase in Kitaev's honeycomb lattice model

2008

The spectral properties of Kitaev's honeycomb lattice model are investigated both analytically and numerically with the focus on the non-abelian phase of the model. After summarizing the fermionization technique which maps spins into free Majorana fermions, we evaluate the spectrum of sparse vortex configurations and derive the interaction between two vortices as a function of their separation. We consider the effect vortices can have on the fermionic spectrum as well as on the phase transition between the abelian and non-abelian phases. We explicitly demonstrate the $2^n$-fold ground state degeneracy in the presence of $2n$ well separated vortices and the lifting of the degeneracy due to t…

PhysicsQuantum PhysicsPhase transitionCondensed Matter - Mesoscale and Nanoscale PhysicsSpinsStrongly Correlated Electrons (cond-mat.str-el)quantum computationnon-abelian vorticesGeneral Physics and AstronomyFOS: Physical sciencesFermionkitaev's modelVortexCondensed Matter - Strongly Correlated ElectronsMAJORANAanyonsLattice (order)Quantum mechanicsMesoscale and Nanoscale Physics (cond-mat.mes-hall)topological modelsNon-abelian vorticeAbelian groupGround stateQuantum Physics (quant-ph)
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