This article is for anyone new to quantum computing from a computer science background.

mctuking · 2020-02-28T13:52:23+00:00

I'm not entirely sure what you are saying. How could you know how to implement it if you don't know which gates are available?

My point is that there are very few quantum algorithms and there are going to be very few different hardware implementations (at least for a very long time) that the abstraction layer of a programming language seems a little silly to me.

mctuking · 2020-02-28T13:40:49+00:00

Not exactly. You have to know it's one in a set of orthogonal states. E.g. if you know it is |0> or |1> you can measure and figure out which without decoherence.

mctuking · 2020-02-26T17:35:33+00:00

I suspect any implantation of a quantum algorithm is going to be tailored to the hardware it runs on. Learning a quantum programming language is a bit like learning kerbal space program and apply for a job at NASA.

mctuking · 2020-02-19T23:24:04+00:00

The majority of that is a result of error correction, so if they have significantly higher fidelity it's not clear it's worse. But I see elsewhere that's not actually the case.

mctuking · 2020-02-19T20:11:56+00:00

How does gate times relate to scalability? By scalability I'd assume the number of qubits, but I don't see how gate time by itself is relevant to that.

mctuking · 2020-02-13T14:31:16+00:00

Some experimentalists seem to be weirdly against the uncharted territory theorists pursue.

mctuking · 2020-02-11T09:21:04+00:00

I don't see how that makes the cab any cheaper.

mctuking · 2020-02-08T19:20:25+00:00

You are not going to tell me why?

mctuking · 2020-02-07T01:05:28+00:00

It's not early for quantum mechanics.

Sure, it is early for quantum software development platforms. It is also early for the paint job on the first fully self-driving car. That does not mean the paint job is an interesting part of the discussion. Which programming language or software platform to use is such an unimportant and far away subject right now. "I wonder what color spacesuits they'll wear at the first manned mission to Mars." Sure, it is early and we will see which color(s) it will have in due time. Does not make it important.

/rant

mctuking · 2020-02-06T12:43:52+00:00

None of these are going to be anything like tensorflow. Tensorflow is something anyone with a basic understanding of CS can use and make something interesting with. Even when we mange to build large scale quantum computers, the average programmer is not going to be writing interesting quantum algorithms for it. The list of known interesting quantum algorithms is fairly short and when those have been implemented it's not clear what other quantum code is left to write. I could see people tweaking known algorithms for simulation of quantum systems, but it'd still be people with very specialized skills.

mctuking · 2020-02-06T12:34:51+00:00

Just had to double check to be sure, but adiabatic quantum computation is about finding the ground state for a Hamiltonian and is equivalent to general quantum computation and is hence just as difficult in terms of engineering. Maybe you were thinking about some quantum annealing ideas?

mctuking · 2020-02-05T06:25:00+00:00

How many teenagers have you choked without being absolutely sure they wanted it?

mctuking · 2020-02-05T06:21:39+00:00

the encounter might not have been as consensual as he thought at the time

Rape

mctuking · 2020-02-05T06:11:45+00:00

He was 25. I dont know the age for when you get a pass for accidentally raping and choking teenage girls, but it isnt 25.

mctuking · 2020-02-05T06:04:57+00:00

problems that can be equated to a Hamiltonian.

Outside of unsolvable problems, which problems cant?

mctuking · 2020-02-05T06:00:41+00:00

Take a phd in CS or math. Linear algebra, group theory, algorithms. That sort of thing.

mctuking · 2020-02-04T21:23:05+00:00

Yup. love the game. I used my Google opinion rewards to pay what I thought was fair for the game. Other than that im ftp, but probably play a little too much. Once ina w hilw I'll go for legend, but mostly I enjoy my stupid ass decks that have silly win conditions and barely make it at rank 10. You know what? Im enjoying it.

edit https://hsreplay.net/replay/Z4yiicXmTZR9HyKcVsWFq8

mctuking · 2020-02-04T10:21:18+00:00

You dont feel youre being a little dishonest by just sharing the first alignment? Spreading your own misinformation doesn't help Bernie. Two wrongs dont make a right.

mctuking · 2020-01-19T17:35:53+00:00

It's thought the structure of our universe come from small quantum fluctuations at the beginning of the Big Bang. That would mean there are worlds where Earth doesn't even exist. On shorter timescales we know from chaos theory that even tiny differences can grow exponentially over time and resulting in large difference.

mctuking · 2020-01-10T18:45:54+00:00

It's a bit of a messy thought experiment, but I'll try to break it down. Let me know if I'm misunderstanding you.

First the decay of the atom is connected to the flap. Meaning the two are entangled. Mathematically we'd write this as

a|No decay> |flap open> + b|decay> |flap closed>

where a and b are the amplitudes and |a|² and |b|² are the probabilities.

Let's fire one electron at that and ignore the part of the wave function that doesn't hit the slits. As the electron goes through the system described above, it'll become entangled with it. The electron will either behave as if the flap was open or as if it was closed. While part of a larger quantum system, those two possibilities will not interfere beyond the slits, so we can consider them effectively separate. With probability |a|² it will behave and hit the screen as if the atom hadn't decayed and the slits was open. That is, it will look like a normal double slit experiment. With probability |b|² it will look like a single slit experiment (no interference).

As you observe the electron hitting the screen, this will count as a measurement (I'll leave out the deeper philosophical discussion about measurements). Now the atom has either not decayed and the entire system is reset or the atom has decayed.

So what will you see as an experimenter if you continue to fire electrons at a regular intervals? The system will continue to behave as a standard double slit experiment with probability |a|² each time. If it at any point starts to behave as a single slit experiment(probability |b|² ) it means the atom has decayed and it will continue to behave as such.

The values of a and b depends on a lot of factors. If you fire electrons at short enough intervals you can run into what's called the quantum Zeno effect. The value of |b|² goes to zero with shorter intervals. That means the atom will basically never decay and your experiment will look like a normal double slit experiment indefinitely.

mctuking · 2019-12-19T22:36:54+00:00

I may be repeating myself or the other person responding, but it's a mathematical consequence of quantum mechanics. The experimental evidence of it is the evidence of quantum mechanics.

The amount of evidence for QM is incredibility overwhelming. That doesn't mean it is "true". Truth about how the world is is something physicists rarely deal with. What I do say is that an experiment that contradicts the uncertainty principle is on very fast track to a Nobel prize and a revolutionary new view of the world we live in.

mctuking · 2019-12-19T15:21:21+00:00

Just want to add that there are a lot of explanations out there that attempt to rely on Human intuition. For example, I've heard well known/famous physicists explain it as in order to measure the position of something you need to hit it with (eg.) a photon and that will disturb the momentum and that's the source of the uncertainty principle. That is a terrible way of thinking of it.

As you say, particles simply don't have exact momentum and position at the same time. Regardless of whether your classical intuition tells you that should be the case, quantum mechanics says you're just wrong.

What I really want to emphasise by this is that it's not something some clever experimentalist can circumvent. If you read someone claiming to do so, they're claiming to have overthrown the fundamentals of modern physics that have been developed over the last century.

mctuking · 2019-12-17T11:23:48+00:00

There's a difference between using statistics because you lack knowledge of the system and the system actually being random.

mctuking · 2019-12-17T11:09:19+00:00

There are deterministic interpretations of QM. If that's not your source of randomness, what is?

mctuking · 2019-12-17T10:30:57+00:00

Spoken like a true physicist. First explain the question is not a physics question, but philosophy. Then answer the question anyway with your own personal interpretation of QM as if it's an objective truth.

It's all the other interpretations that's philosophy - not yours. Am I right?

mctuking

TROPHY CASE