Abstract
The high fidelity generation of strongly entangled states of many particles, such as cat states, is a particularly demanding challenge. One approach is to drive the system, within a certain final time, as adiabatically as possible, in order to avoid the generation of unwanted excitations. However, excitations can also be generated by the presence of dissipative effects such as dephasing. Here we compare the effectiveness of Local Adiabatic and the FAst QUasi ADiabatic protocols in achieving a high fidelity for a target superposition state both with and without dephasing. In particular, we consider trapped ions set-ups in which each spin interacts with all the others with the uniform coupling strength or with a power-law coupling. In order to mitigate the effects of dephasing, we complement the adiabatic protocols with dynamical decoupling and we test its effectiveness. The protocols we study could be readily implemented with state-of-the-art techniques.
Highlights
The possibility of generating many-body entangled states has important consequences in metrology [1,2,3,4] and in quantum computation [5]
Once we introduce the dynamical decoupling term, the fast quasi adiabatic (FAQUAD) protocol can reach a maximum fidelity up to a 7% higher F F = 0.9523 when ω = 553.7 Hz, whereas the result for local adiabatic (LA) does not improve for the parameters explored
We have considered setups that can be realized experimentally with trapped ions, both with uniform and power-law interactions
Summary
The possibility of generating many-body entangled states has important consequences in metrology [1,2,3,4] and in quantum computation [5]. It is necessary to use a strategy that allows, simultaneously, both the preparation of a target state quickly, reducing the possible excitations from the Hamiltonian driving, and the protection of the system from the effects of dissipation. In this work they studied, both theoretically and experimentally, the evolution of ions in a Penning trap They prepared a system in a product state in the presence of a large magnetic field, and reduced the magnetic field to drive it to a cat state. For the latter, we will consider the effect of dynamical decoupling.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
