4:00 PM
We'll go through the questions posed in the meta post in order of up-votes, but of course this is a conversation so please ask anything else you'd like to know as we go along. When we switch to a new main topic I'll make a post in bold with the question we're discussing.
During the AMA, if you think of a big question that's not really related to whatever we happen to be discussing at the time, please just post it in this other chat room. I'll keep that room open in another window so I can see incoming questions.
hi all welcome Daniel Sank Phd! could write long intro here, trying to be brief. world class Martinis QM computing lab acquired by Google ~3rd Q 2014. DS has been working there several years. hes one of the rare Phds very active on the site & in the chat room. home pg/ links to a lot of excellent coverage starting here, esp MIT tech review has great articles chat.stackexchange.com/transcript/message/31649921#31649921 thx very much DS & audience for attending. =D
> I have found that a true understanding of noise is absolutely essential to my work, and was mostly omitted from my education!
I am facing a similar problem! I would like to ask: How did you acquire your knowledge about this branch of statistical mechanics? Would you be able to provide any good references? Most standard statistical mechanics books seem to be omitting this topic largely. I found some stuff in Altland and Simons, but would appreciate your input and potentially a systematic structuring of how to learn about the topic.
4:06 PM
4:10 PM
I think part of the problem is that to understand noise you have to understand statistics and signal processing at the same time.
@JohnRennie Funny you should mention that. As a student I hated the fact that in the lab classes they always said "blah blah counting statistics" but nobody ever explained where that damned sqrt(N) comes from.
Yeah so, while I was a grad student there was this renaissance in superconducting parametric amplifiers.
@EmilioPisanty More or less, although at this point we're limited in the noise performance by the fact that the wires we having going from the quantum limited amplifier to the next stage HEMT amplifier (shouts out the astro people in the room) are lossy.
The hardest thing about quantum measurement for us now is turning the measurement device on and off fast.
What inspired or motivated you to become a physicist? Were any teachers or family particularly important? or did you discover science yourself through books, TV and the internet? Were there ever any barriers - financial or social, or other - to your career or education? If so, how did you overcome them?
Well, definitely my dad to a large degree. He's a physicist (works for NASA) and when I was a kid, every question I asked how about stuff works was met with "Now remember the universe is made of atoms...".
4:21 PM
Regarding heroes, I'd say that wasn't a huge influence. I did always take note that Einstein was able to figure out a huge amount of new stuff by following lines of reasoning to their logical conclusion.
Private school for 3rd, 4th, and 5th grades because the elementary school wasn't too crowded/crazy at the time.
Teacher knew I was good at physics etc. so he asks "Hey Sank, how come you never finish your tests? You get every question you do correct, but you don't finish. What gives?"
For like forty years we've all known that superconducting metals exhibit magnetic noise. This noise is a huge problem for superconducting qubits.
He's fanned the flames of interest in the theory community to model the system and understand what's going on.
Your opinion on the current existing system of higher education over the world. What do you believe for the way the Masters and PhDs are working in physics. For example, do you think that they are too much directed towards the needs of the working sector or not. Any ideas and experiences on the field. Also, maybe a brief discussion for the PhD program of the USA, do you think it works, should it be like this, is it a good opportunity for someone to study physics in the US and why?
4:35 PM
It's too much memorization and not enough focus on what's going on and how to use it to do interesting stuff.
I spent every single summer as an undergraduate re-discovering and re-inventing all the mathematics I needed in order to really understand my physics books.
How many of us have been confused by coordinate transformations, or this ridiculous issue of "active" versus "passive" transformations?
Part of Constantine's question was about whether education is too tailored toward the working sector.
I was not required to learn basic electronics as a physics undergraduate. This, in retrospect, was ridiculous.
It was motivated by the fact that none of my classes ever introduced it until my quantum mechanics prof. started using it.
We were all like "what the hell is that?" and he eventually became exasperated and said "look, it's just a basis transformation".
So, I spent all summer working out the details of that and coming up with a notation to make it all clear.
I eventually worked it all up into a series of two "lectures" which I presented at an undergraduate journal club.
We had these little feedback cards where you write stuff so that the speaker could learn to improve.
Here's my work from that summer. It needs a lot more work and the TeX might not build right now as I moved everything from an old SVN repo to github.
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Quantum computing has been around now for nearly forty years, and hasn't delivered anything. Meanwhile ordinary computing has advanced in leaps and bounds. So: is quantum computing just some two-bit jam-tomorrow hype that's never going to deliver anything? Is it going to quietly fade away like string theory, having consumed millions of publicly-funded man-hours, all for nought? Man hours that could have been productively spent on say optical computing, as per Taming Light at the Nanoscale?
We've invented quantum limited amplifiers, we've discovered all kinds of stuff about what causes loss at the quantum scale in solid state devices, we've violated the Bell inequality in new ways with far higher certainty than ever before...
John's right that we haven't beaten classical computers on anything yet, much less any economically important problems.
....but we're getting there. When I started grad school doing single qubit experiments was a big deal.
We've improved the coherence of our qubits by more than a factor of 100x since I started as a grad student.
Other groups have even higher coherence than we do (at the cost of other stuff... it's always a trade-off).
As for allocation of man-hours... while I agree that we would all like to spend time on the most important and beneficial stuff, I think it's completely unrealistic to expect scientists to go work on whatever "you" think is the most important thing.
At Google, if we discover that we need to adjust our course, the higher-ups understand that we know what we're doing.
4:54 PM
@JohnRennie It's very exciting. People are really into what they do, and interested to hear about our work.
We even have help from people doing things like e.g. programming our FPGA's, and even laying out lithography masks for our devices.
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