Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Many-Body Echo   In this letter we propose a protocol to reverse a quantum many-body dynamical
process. We name it "many-body echo" because the underlying physics is closely
related to the spin echo effect in nuclear magnetic resonance systems. We
consider a periodical modulation of the interaction strength in a weakly
interacting Bose condensate, which resonantly excites quasi-particles from the
condensate. A dramatic phenomenon is that, after pausing the interaction
modulation for half a period and then continuing on with the same modulation,
nearly all the excited quasi-particles in the resonance modes will be absorbed
back into the condensate. During the intermediate half period, the free
evolution introduces a $\pi$ phase, which plays a role reminiscent of that
played by the $\pi$-pulse in the spin echo. Comparing our protocol with another
one implemented by the Chicago group in a recent experiment, we find that ours
is more effective at reversing the many-body process. The difference between
these two schemes manifests the physical effect of the micro-motion in the
Floquet theory. Our scheme can be generalised to other periodically driven
many-body systems.

30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio