What is a wave?

It's actually something like a wave,

which is sort of wobbling around

in some potential with which I trap it.

So it is very much like transporting some liquid, okay?

And if I want to transport some liquid from here to there,

let's say that, you know, today,

Enrique invited me and of course there is limited time,

so he gave me like one hour for speaking,

but I have things which I want to tell you,

which is for four hours.

So I would like for him not to realize

when one hour has passed.

So I need to get him drunk, okay?

I hope that he likes champagne.

And here I have a source of champagne,

which is very cold and pleasant, okay?

I just put it in my glasses, okay?

I fill my glasses with the brim,

I have to deliver it to him.

And then, you know, what can I do?

I want to deliver to maximize the amount of champagne

that he will drink, so I can, you know, physically,

I can transport this adiabatically, okay?

Adiabatically means without having any excitation,

so I will very, very slowly do this.

After a long time, I will get here,

but there is a problem because I cannot take all the time

that I want for quantum processes because there is,

I need to, there is the need to preserve quantum coherence.

So the interaction with the environment, okay,

will heat up my system, the champagne will be warm,

it will not be, you know, agreeable,

and so he will not drink it.

So what I can do, of course, is I can obviously try

to restart, and then, you know, I will do this

with some sort of linear time dependence,

I will do it like this, but of course, if I do this,

I have non-adiabatic transitions in the sense

that my glasses will fall to the ground,

and so my fidelity will also fall to the ground.

So what I can do is, and this is obvious to all of you,

you know, of course, I use all my control parameters,

I will tilt my cup, I will come there, and I will serve.

So in quantum terms, it means I am exciting my system

to a higher energy state, and then I have to use

quantum interference to go, which is something

exquisitely quantum, the fact that, you know,

quantum states, they combine linearly.

So the final state, if I excite more than one state,