A method is introduced to realize dispersion-free transport of a localized wave packet on a lattice by devising a Hamiltonian so that the wave packet perfectly splits and interferes with itself, providing a new avenue in the field of perfect state transfer.
The possibility to designing schemes useful for developing quantum technology devices of practical value necessitates exploiting quantum coherence effects in a scalable physical system in a feasible way. The broad aim of this thesis is to investigate the use of quantum non-equilibrium dynamics for the above, exploiting minimal control to accomplish highly coherent dynamics in a many-body system. How to harness the natural hopping dynamics of particles in a many-site lattice for controlled applications, is still an open question. Through the introduction of few impurities in the lattice potential, we devise a scheme to trigger effective tunable linear optics-like operations between arbitrary sites, that overcomes the limitations of setups based on coherent hopping dynamics, when particles are initially separated by many sites. Our scheme enables the generation of peculiar quantum interference effects as well as quantum metrology applications in a many-site lattice. We design a lattice coupling profile that enables perfect wave-packet splitting between mirror symmetric sites and leads to perfect wave-packet reconstruction, fractional revivals and perfect entanglement distribution, for arbitrary long chains. We prove that composite objects in a lattice, made of more particles initially in a lattice site, are a valuable resource for dynamically generating non-classical states between remote sites, tackling edge-localisation effects via local fields. Finally, we show how the spin independent scattering of two initially distant qubits, can be used to implement an entangling quantum gate between remote sites of a lattice. Our findings have potentially an impact on quantum information, as well as on atomic interferometry in a lattice.
We propose a robust and efficient way to store and transport quantum information via one-dimensional discrete time quantum walks. We show how to attain an effective dispersionless wave packet evolution using only two types of local unitary operators (quantum coins or gates), properly engineered to act at predetermined times and at specific lattice sites during the system's time evolution. In particular, we show that a qubit initially localized about a Gaussian distribution can be almost perfectly confined during long times or sent hundreds lattice sites away from its original location and later almost perfectly reconstructed using only Hadamard and ${\ensuremath{\sigma}}_{x}$ gates.
We propose a robust and efficient way to store and transport quantum information via one-dimensional discrete time quantum walks. We show how to attain an effective dispersionless wave packet evolution using only two types of local unitary operators (quantum coins or gates), properly engineered to act at predetermined times and at specific lattice sites during the system's time evolution. In particular, we show that a qubit initially localized about a Gaussian distribution can be almost perfectly confined during long times or sent hundreds lattice sites away from its original location and later almost perfectly reconstructed using only Hadamard and σx gates.