MeidokonWiki:

An assortment of topics and thoughts that might be helpful for interviews and resumes, etc.

Palantir

I interviewed with Palantir in early 2019. Not successful, but I got a free trip to San Francisco for what I guess was a final round of interviews!

These aren't all questions I was asked, they're questions that I prepared for.

There were about 4-5 phone/zoom interviews in total before I got asked to go to San Francisco. The recruitment team were very communicative the whole way through, lots of emails and calendar scheduling, and could do a lot of the talking and question-answering before passing me to the people inside that'd do the real interviewing.

Questions to ask them in the interview

About the hiring process

Why Palantir?

Really exciting problems to solve! I'm interested in having breadth of systems to learn and deal with.

Stuff you'd like to learn or play with

Stuff you've made

Pain points in current role

What I've learnt at my current job

People. People are a challenge.

Stuff you do in your spare time

What other roles have you been exploring and why not those ones

Talk about something deeply technical you've done

LD_PRELOAD fun

At Dept of Education.

Hack the On2/Flix media encoder to transfer the software licence, when the original company is defunct. Dig into the code and hijack the call where it gets the MAC address and hostname, LD_PRELOAD fun, etc.

That was cool because I learnt a bit about deeper system internals, and got to pay off some crappy tech debt.

But that's nothing compared to starboard...

SMFT

At Dept of Education.

SMFT for file transfers, fixing up the encryption, knowing that the automation works, getting it monitored, monitoring it by sending files!

ldapmanage tooling

At Dept of Education.

ldapmanage tooling was fixed and extended, got the reporting working again (expiring and soon-expiring accounts)

Something interesting you saw or read recently

Questions to ask about the company and practices

Small talk topics

One of my technical interviewers lived in DC, so I planned some questions for them.

Q-CTRL

I interviewed with Q-CTRL in March 2019. I was that close to getting hired and it's the most enjoyable interviewing I've ever done. Ultimately they said No because they couldn't be 100% confident in saying Yes, and I think they made the right decision. At the time Q-CTRL was a very small startup and I would've been a technical linchpin for all their operations. The role would've required leadership a bit beyond my experience, so it'd be a risky decision (and probably very stressful for me if I got it).

This is something I was thinking of publishing to twitter, about what I learnt about what their business does.

Praise the Lord, I had a really good interview! I *think* I can also explain the idea of "quantum control" now in layman's terms, so here goes:

At the heart of any quantum computer is the "qubit", it's like a regular digital bit but quantum-y. Qubits are only useful when they're in a state of quantum superposition, which is the whole "it can be two things AT THE SAME TIME" feature.

Qubits are really fragile, they'll fall out of this superposition state if you even look at them, literally. So we want to work on qubits without disturbing them too much, and we do this by removing as much interference and noise from the system as possible. This means stuff like shielding the quantum computer from radio/electrical interference, and cooling them down to as close to absolute zero as possible (roughly -273 degrees C).

The analogy I'm going to use here is tightrope walking. Imagine you need to cross a tightrope and you're carrying a qubit with you, it just chills out and sits on your head or something. You're also holding a stick with some weights on the end to help you balance.

In an ideal situation, the rope doesn't move and there's no wind or anything to throw you off balance - super easy. In reality, it's hard to focus perfectly as you walk across the rope, and sometimes you jitter around as your muscles try to keep your body balanced. You also have to struggle with gusts of wind, which you need to compensate for to stay on the rope. These are all unpredictable disturbances

If you fall off the rope then you drop the qubit and it's no good, you have to go back and try again. This is called "decoherence", which is a something that you try to manage. Quantum control is about mitigating disturbances, and delaying or avoiding decoherence.

Reducing external noise and interference is like shielding yourself from the wind while walking the tightrope, so the gusts are much weaker. The wind gusts also tend to follow a pattern, even if it's not entirely predictable. If you know when it's coming, you can lean into the gusts and hopefully not get thrown off balance.

If you train your muscles to be stronger, and improve your muscle coordination through practice, it's much easier to balance on the rope because your movements are more relaxed and precise. For a quantum computer this might equate to a power supply that can maintain the voltage very precisely, or a laser with more consistent pulses (lasers are used to manipulate qubits).

Carrying a longer or heavier stick also makes it easier for you to balance, but I don't have a quantum analogy for this one. Maybe IBM just sells you a more expensive quantum computer, because the stick is made of platinum or something. :P

It's very similar to noise-cancelling headphones, if you think about it. If you know what the noise sounds like, you can make an inverted copy of the noise and cancel it out. Quantum control roughly amounts to that, compensating for inherent noise in the system, and finding ways to nullify it. Simples!

MeidokonWiki: furinkan/JobInterviewNotes (last edited 2021-04-19 15:23:20 by furinkan)