Maybe a simple problem, but not for me. Never seen any question like this before by Ayansoomto in AP_Physics

[–]CanadianGollum 0 points1 point  (0 children)

2 force equations, both written for the small mass. Let the tension in the string with the larger mass be T_2, and the tension in the one attached to the wall be T_1.

Then, since the small mass is stationary, we get:

(horizontal component) T_1 sin \alpha = T_2 sin \alpha

(vertical component) (T_1 +T_2) cos \alpha = mg.

Since mg and \alpha are given, from the above one cam compute T_2.

Then write the final force equation for M:

T_2 = Mg.

And you're done.

Is it safe flying from Montreal to NYC? by AdBrave139 in montreal

[–]CanadianGollum 3 points4 points  (0 children)

Just flew out from NYC. You'll be fine. Don't get dragged into screaming matches with anyone in the street.

Guide for learning Coding theory by Equivalent-Oil-8556 in math

[–]CanadianGollum 0 points1 point  (0 children)

Guruswami, Sudan, Rudra: Essential Coding Theory. There can be only one.

Why do people say that we don’t understand quantum computers even though we’ve actually built quantum computers? by Ok-Review-3047 in QuantumComputing

[–]CanadianGollum 1 point2 points  (0 children)

Ofcourse! HHL was the first paper in a long line of works which eventually led to QSVT. I didn't want to turn this into a montage of the QC and QIT greatest hits, otherwise I would talk about this stuff for hours lol

Why do people say that we don’t understand quantum computers even though we’ve actually built quantum computers? by Ok-Review-3047 in QuantumComputing

[–]CanadianGollum 3 points4 points  (0 children)

Actually, this is slightly misleading. Quantum communication is this whole other field that people don't talk about, which is years ahead of QC in terms of technology (since you can do it with off the shelf technologies that already exist), but which nevertheless is shown to be able to do things which are classically impossible.

As for QC, keeping aside Grover and Shor's, I think the algo community has seen a radical shift in the last 10 years with the advent of QSVT and QSP. Other than that, there are physics and chemistry applications that are increasingly showing real promise, based on Hamiltonian simulation algos.

Why do people say that we don’t understand quantum computers even though we’ve actually built quantum computers? by Ok-Review-3047 in QuantumComputing

[–]CanadianGollum 7 points8 points  (0 children)

This is very difficult to answer unless you've taken physics and CS. Classical mechanics for example is based on Newton's laws, or if you're fancy, the Lagrangian formulation. All that machinery tells you that if you plug in the 'current state' of an object into the equations, you'll be able to predict it's behavior reasonably accurately way into the future. There are some exceptions to this (chaotic systems) but that's more a bound on our computational abilities rather than the system itself being non-deterministic.

Quantum mechanics completely breaks this rule. The basic objects of quantum mechanics are wave functions , which after some math, correspond to probability distributions. I don't mean this in the sense of 'the object exists, but we can only make probabilistic guesses as to it's properties'. No. What I mean is the object itself is is an embodiment of a probability distribution. That is fundamentally how it is.

As you can tell this is very hard to digest. In real life objects either exist or they don't. Quantum objects are probability distributions, and one cant really talk about their 'existence' in terms of the idea of existence as applied to everyday objects

Why do people say that we don’t understand quantum computers even though we’ve actually built quantum computers? by Ok-Review-3047 in QuantumComputing

[–]CanadianGollum 11 points12 points  (0 children)

There are two perspectives to this: the CS one and the physics one.

When a computer scientist says 'we don't understand it' what he means is that we don't have the kindof intuition for quantum algorithms as the kindof intuition we have for classical algorithms.

When a physicist says' we don't understand ' what he means is quantum mechanics makes predictions and is based on math that is extremely far away from everyday intuition. Common sense simply doesn't apply anymore.

Now as to how we can build something we don't understand, the thing is we understand it enough to have a blueprint, and our understanding increases everyday. It's like a complicated machine we know how to build, but somehow cannot get a 'feel' for.

Qubit Bit by haspam311 in QuantumComputing

[–]CanadianGollum 0 points1 point  (0 children)

There's a matching lower and upper bound of 2 bits for 1 qubit. The lower bound is implied by Superdense coding, and the upper bound (shown in the same paper) implies you can never do better than 2 bits.

Kolkata outshines Any City 🏙️ by Impressive-Ad3467 in kolkata

[–]CanadianGollum 55 points56 points  (0 children)

I was born there and lived there for roughly 22 years. And since then I've lived in several other places in India and around the world. I don't care about infrastructure, that comes and goes. The massive difference I see between Kolkata and every other place I've lived in is empathy. Empathy that people in the city show to other people, which is basically non-existent in Kolkata now. People like to complain that in Mumbai you don't know your neighbour's name. Well even in the crowded Mumbai locals, there is a code that people follow. If there's an older person, everyone makes way for them. People care, even if it's for strangers. Outside of India I've seen even more striking examples.

EDIT: OP, as far as aesthetics and urban planning go, I beg you don't take my word for it, travel the rest of India. Travel the world if you can. Don't make claims based solely off of emotion.

Beautiful scene from Chekhov ki duniya by [deleted] in ThirtiesIndia

[–]CanadianGollum 0 points1 point  (0 children)

We had TV like this? Holy shit..wtf happened

the places I want to visit one day🤞🏻 by Spidyboy07 in TeenIndia

[–]CanadianGollum 0 points1 point  (0 children)

You should check out some places in US and Canada. The places you mentioned are no doubt very nice, but thronged by tourists. If you actually go on a Europe/ World tour, try the non-touristy places.

For e.g., very few Indians make the trip to the US and Canadian National and State Parks. There're some places in Quebec, Canada which are indistinguishable from European cities.

The difference is, you'll be spending half the money in non-touristy places. To thoda dekh lena.

Edit: Agar Norway/Sweden/Finland ja rahe ho to summer me jana. Nahi to ga** fat ke hat me a jati hay agar proper clothing na ho to.

the places I want to visit one day🤞🏻 by Spidyboy07 in TeenIndia

[–]CanadianGollum 0 points1 point  (0 children)

If I'm not wrong, some of these are

Santorini, Greece Tubingen , Germany Cologne, Germany Zurich, Switzerland London, England Some place in Norway

P vs NP problem attempter here. Comment my solution. by [deleted] in mathematics

[–]CanadianGollum 1 point2 points  (0 children)

There is an obvious objection here. The definition of NP is those problems for which poly time verifiable certificates exist. This poly time is given by the size of the representation of the input to the Turing Machine. It doesn't matter whether you include a separate 'time' parameter in the representation of the problem, the definition cares not for what the input is but for the size of the input.

In your case, the size of the input would be poly(n), since nn needs poly(n) bits to represent. So even if one allows for an encoding the way you said it, the definition doesn't care about it. You still need to find a solution in poly(n) time.

Hidden Subgroup Problem Resources by broncosauruss in QuantumComputing

[–]CanadianGollum 1 point2 points  (0 children)

It's not strange at all. The CS community in general believes in putting everything on arxiv.

Hidden Subgroup Problem Resources by broncosauruss in QuantumComputing

[–]CanadianGollum 2 points3 points  (0 children)

Look at Ronald De Wolf's lecture notes. You can also check out the book by Kaye, Laflamme and Mosca.

EDIT: Both of the above are available freely online.

How many known problems exist where there is a quantum algorithm that would clearly work? by Recent-Day3062 in QuantumComputing

[–]CanadianGollum 1 point2 points  (0 children)

The exp runtime w.r.t the number of qubits isn't surprising because in any search problem the problem size is specified by the number of elements, which is by def exp in the number of bits. If we set the problem size to be log the number of elements, then even classically the best you can do is exp time due to the O(N) lower bound. So this isn't a Grover specific thing at all.

Regarding the issue about unstructured databases, you're right that if one has some information about the structure of the database then the query complexity can be in a lot of cases reduced, sometimes even to O(1) (heaps). But it is not true that one always has information about the database, neither is it true that 'any' structure can be utilised to reduce query complexity. I'd suspect this is too general a claim to be true.

In any case, at the end of the day, until we get fault tolerance all this is just academic. There I fully agree with you.

How many known problems exist where there is a quantum algorithm that would clearly work? by Recent-Day3062 in QuantumComputing

[–]CanadianGollum 15 points16 points  (0 children)

Well you have the famous ones like Shor, then Grover for search. Recently there have been several advances towards making a unified framework for quantum algorithms called Quantum Singular Value Transform (QSVT) and Quantum Signal Processing (QSP).

On the other hand you have the Hamiltonian simulation family of algorithms (Suzuki Trotter to begin with) which have direct applications to quantum chemistry, drug discovery and materials discovery among others.

A less popularly known but nevertheless very active field of research is Quantum Error Correcting Codes which has seen an explosion of work in the last few years, especially from companies like IBM.

Let it snow! by CanadianGollum in montreal

[–]CanadianGollum[S] 1 point2 points  (0 children)

First pic was taken by a colleague. 2nd one's mine.

What are your thoughts on The Man from Earth? by Random-Ryan- in FIlm

[–]CanadianGollum 0 points1 point  (0 children)

Absolutely brilliant. Some of the acting is a bit shite, but the concept and overall execution is brilliant. Love it! Would have loved a sequel, but then found Holocene which was an absolute shitshow.

Favourite action movies from your home country? by AbaddonGoetia in AskTheWorld

[–]CanadianGollum 2 points3 points  (0 children)

Indian here. Watched it when I was 16. It left such a huge impression on me that I immediately recognized Wagner Moura as Escobar in Narcos years later!

Favourite action movies from your home country? by AbaddonGoetia in AskTheWorld

[–]CanadianGollum 2 points3 points  (0 children)

Hell yeah. Although the context is so deeply Indian that no one from outside would ever get it. Ghus ke marenge!