= IonQ
{c}
{tag=Company}
{title2=2015}
{wiki}
\Video[https://www.youtube.com/watch?v=LEqPlDrMXjs]
{title=Quantum Simulation and Computation with Trapped Ions by Christopher Monroe (2021)}
\Video[https://www.youtube.com/watch?v=9aOLwjUZLm0]
{title=Quantum Computing with Trapped Ions by Christopher Monroe (2018)}
{description=
Co-founder of <IonQ>. Cool dude. Starts with basic background we already know now. Mentions that there is some relationship between <atomic clocks> and <trapped ion quantum computers>, which is interesting. Then he goes into turbo mode, and you get lost unless you're an expert! <video Quantum Simulation and Computation with Trapped Ions by Christopher Monroe (2021)> is perhaps a better watch.
* https://youtu.be/9aOLwjUZLm0?t=1216 <superconducting qubits are bad because it is harder to ensure that they are all the same>
* https://youtu.be/9aOLwjUZLm0?t=1270 our wires are provided by <lasers>. Gives example of <ytterbium>$^{+1}$, which has nice frequencies for practical <laser> choice. Ytterbium ends in 6s2 5d1, so they must remove the 5d1 electron? But then you are left with 2 electrons in 6s2, can you just change their spins at will without problem?
* https://youtu.be/9aOLwjUZLm0?t=1391 a single atom actually reflects 1% of the input laser, not bad!
* https://youtu.be/9aOLwjUZLm0?t=1475 a transition that they want to drive in Ytterbium has 355 nm, which is easy to generate TODO why.
* https://youtu.be/9aOLwjUZLm0?t=1520 mentions that 351 would be much harder, e.g. as used in inertially confied fusion, takes up a room
* https://youtu.be/9aOLwjUZLm0?t=1539 what they use: a <pulsed laser>. It is made primarily for <photolithography>, <Coherent, Inc.> makes 200 of them a year, so it is reliable stuff and easy to operate. At https://www.coherent.com/lasers/nanosecond/avia-nx we can see some of their 355 offers. https://archive.ph/wip/JKuHI shows a used system going for 4500 USD.
* https://youtu.be/9aOLwjUZLm0?t=1584 Cirac and Zoller proposed the idea of using entangled ions soon after they heard about <Shor's algorithm> in 1995
* https://youtu.be/9aOLwjUZLm0?t=1641 you use <optical tweezers> to move the pairs of ions you want to entangle. This means shining a <laser> on two ions at the same time. Their movement depends on their <spin>, which is already in a superposition. If both move up, their distance stats the same, so the <Coulomb interaction> is unchanged. But if they are different, then one goes up and the other down, distance increases due to the diagonal, and energy is lower.
* https://youtu.be/9aOLwjUZLm0?t=1939 S. Debnah 2016 Nature experiment with a pentagon. Well, it is not a pentagon, they are just in a linear chain, the pentagon is just to convey the full connectivity. Maybe also <Satanism>. Anyways. This point also mentions usage of an <acousto-optic modulator> to select which atoms we want to act on. On the other side, a simpler wide laser is used that hits all atoms (<optical tweezers> are literally like tweezers in the sense that you use two lasers). Later on mentions that the modulator is from Harris, later merged with L3, so: https://www.l3harris.com/all-capabilities/acousto-optic-solutions
* https://youtu.be/9aOLwjUZLm0?t=2119 <Bernstein-Vazirani algorithm>. This to illustrate better connectivity of their ion approach compared to an <IBM quantum computer>, which is a <superconducting quantum computer>
* https://youtu.be/9aOLwjUZLm0?t=2354 <hiden shift algorithm>
* https://youtu.be/9aOLwjUZLm0?t=2740 Zhang et al. Nature 2017 paper about a 53 ion system that calculates something that cannot be classically calculated. Not fully controllable though, so more of a <continuous-variable quantum information> operation.
* https://youtu.be/9aOLwjUZLm0?t=2923 usage of cooling to 4 K to get lower pressures on top of vacuum. Before this point all experiments were room temperature. Shows image of refrigerator labelled Janis cooler, presumably something like: https://qd-uki.co.uk/cryogenics/janis-recirculating-gas-coolers/
* https://youtu.be/9aOLwjUZLm0?t=2962 qubit vs gates plot by H. Neven
* https://youtu.be/9aOLwjUZLm0?t=3108 <modular trapped ion quantum computer> ideas. Mentions experiment with 2 separate systems with optical link. Miniaturization and their black box. Mentions again that their chip is from <Sandia>. Amazing how you pronounce that.
}