@0celo7 you do partial measurement. This partially collapses the state.

Then you do state tomography to measure the density matrix.

Then you do that whole thing over again for a different partial measurement strength.

Or a different partial measurement time length.

Whoa, what are those words

:|

@0celo7 You presumably want to replace the second "lengths" with "volumes" in your latest comment

I fixed it already, F5

nooo, length was funnier

I feel like the OP is being intentionally obtuse

@0celo7 You wanna go through it slowly?

hi all

could anyone explains " how to create an article in physics? " and is it possible at the 3rd year grade?

Probably not.

@0celo7 How does it feel? ;)

why?

What age is 3rd grade, anyways?

@Danu Bad I guess.

21 years - 22

@Student404Mus Do you mean 3rd year of university?

yes exactly

@Danu OP's definition of natural is apparently that it shouldn't make sense to use anything else. It's hopeless!

3rd grade is usually used for earlier education, for young children @Student404Mus

He'll probably ask you if there are other connections besides LC.

ok ok

@0celo7 You know that you're like this all the time as well, right? :P

but i mean 3rd year in university

@Student404Mus Anyways, it's definitely possible to write articles at that age. Unless you're extremely good, they won't be all too important though.

@Danu Not at all.

Or if you're lucky, you could be co-author on a paper with some other people

really?

So then it mostly depends on how interested your professors are in working with young students

In Euope, this kind of thing is not very common. In North America, much more common.

anyway i didn't ask my teacher about this topic

out of curiosity, what's the topic?

about creating or publishing articles

I meant the topic of the article you have in mind :-P

ah ? sorry! i don't know

i didn't decide anyway because

It's more feasible to try to contribute to something experimental. Unless you're either extremely good, or your professors give you a big hand, you're probably not going to be able to contribute to any new theoretical physics yet at that time.

i ask my teachers then we will see

good luck

sorry? could you explain please Danu?

There isn't much to explain. Theory is hard.

since i can't speak enlish well

spelling is ahdr

In experiments, there is always a need for people doing some things like working on the machines/equipment, setting up lasers/mirrors and things like that. Undergraduates can do that kind of stuff, I guess.

In theory, there is very little to do except just "come up with things", which usually just takes one or a few people working at a high level of understanding (which is hard for young students).

yes

you are right

I guess that things like computer simulations (if you're good at programming...) could be lower-level work in theory.

but

me personally

i like theoritical physics

How old are you, and what kind of stage in your education are you at?

such as classical and quantum mechanics and

im 21 years almost 22

and studying fundamental physics in 3 rd year level LMD system

what does that mean?

till now i din't do any practical stage if you meant this

@Danu LMD?

LMD system

Well, I've just written an uninteresting answer :-)

Yeah, pretty uninteresting.

:-)

license/Master/Doctora

sorry if it is not written well

because we study at the university using french language

Ah, you're in France?

no friend :) im from algeria

Ah, I see.

Remnants of French colonialism, I guess.

exactly

and i hate that

too much

In any case, if you're into theory, you probably don't need to worry about doing original research/writing research articles for now. Do you have a final/thesis project at the end of the bachelor's degree?

yes in practical activity

what does that mean?

Laboratory?

:D

yes

how do you call it in english

laboratory work

in french it is " Travaux Pratique"

Sure

"laboratory work" good

But there is nothing like a big project (maybe worth half a year or a quarter of a year's worth of study credit) where you go to a professor, find a topic to write something about then spend time learning about it and writing a "thesis" document?

a final project maybe?

yes

@AccidentalFourierTransform final project as you said

So there is something like that?

but not to this level of hardness

you choose the level of hardness lol

Then you can go to a professor who writes about/researches theoretical stuff and write something about theory, try to learn as much as you can and use that to start preparing for research level physics.

So what do you know about besides classical and quantum mechanics? Do you know any field theory (field = champ)? Electromagnetism?

particle physics?

analytical mechanics?

Those topics aren't as interesting with regards to a prospective theoretical physics research :P

I did my final project on the anomalous magnetic moment of the muon :-/

and it was fun and relevant

Depends on what you call theory, I guess ;)

I guess pheno counts; I just don't really think about it

we do experiments in nuclear physics small experiments you know what i mean then we write documents filled by conclusions and graphs and we give them to the teacher and he will evaluate them

But what about theoretical topics?

the muon anomaly is not phenomenology!! :-(

nothing

Did you learn about Maxwell's equations?

@AccidentalFourierTransform Lol :P Yeah it is

yes

in the last year

electromagnetism

Did you learn about tensor notation (for relativistic physics), with the indices?

i think no

because

because of the wonderful things he does

LMD system let us to learn modules briefly

i.e

...

in relativity module we studied essential things only

not deeply

the same thing in all modules

which university are you at?

till we specialise in the next year

i.e?

did you mean the name?

Yeah

Ferhat Abbas in setif

in contrast, classical system let you study modules till you finish very deeply

Is there any list of physics professors online?

i don't know i 'll check

@BernardoMeurer: hi. I've got a great tune for you ..

@JohnRennie Howdy

Which one?

Pff

Come on

I know that!

lol

I love that track

but i don't think so

I know you had some Zep albums but I couldn't remember if they included Zep III

@JohnRennie I'm a Zep fanboy

They were the first music I ever liked

how bout tools cover of no quarter?

YouTube offered it up after I'd played Supernaut and I'd forgotten just how good that track is.

@JohnRennie That song is amazing

@Danu pleased to talk to you

and everybody else

@Student404Mus If you do find one

The whole album is good. Zep III is kind of the forgotten album, but unfairly so.

I could have a look and tell you who of them are doing theory

yes

If you know any professors that do theory, you should/could go to them to ask them what to study extra if you wanna learn more.

i'll back after half an hour

They'll probably tell you (i) relativity (special and/or general) (ii) quantum mechanics (iii) field theory

ok]

thank you

friend i'll back later

bye for now :-)

In a class of its own.

Physical Graffiti is probably their most famous album, but I think it's over indulgent and far from their best album.

Just a personal opinion of course ...

Of course :-)

@JohnRennie I don't like Physical Graffiti that much tbh

@Student404Mus I just went through this list of people working on physics at your university.

Kashmir has always seemed a bit plodding to me. Bonham's drums seem to drag rather than lead.

The people that I think are doing some sort of theory are the following:

researchgate.net/profile/Salah_Menouar

researchgate.net/profile/Kamel_Bencheikh

researchgate.net/profile/Karima_Berkane

researchgate.net/profile/Yacine_Bouguerra

It does plod along...

Do you know any of these people? They could potentially help you learning more theoretical physics.

One of the truly great tracks on Physical Graffiti is Ten Years Gone. It's such a haunting riff.

...methodically over whelming, I'd say.

Indeed that's a beauty.

I'll end with this :-)

This is one of the most awesome guitar solos

True dat pal.

Help... I've fallen down the led zep rabbit hoooolllleee...

Ah ha floyd to the rescue :-)

Good heavens, the price of SSDs has rocketed. Well, it has if you're paying in Sterling. Now what could have caused the pound to depreciate so badly I wonder ...

@JohnRennie Don't worry, once Brexit kicks in y'all will become a #1 superpower again

@Danu thank you very much for your interesting. yes i know some of them like Kamel_Bencheikh

if you don't mind. can you tell me how to sign up on researchgate website without the institutional email?

Mansouri Abdelaziz

Let it be known my last message was ironical

no shit

@AccidentalFourierTransform I rather cover my basis

@Student404Mus I don't know. I didn't sign up for it.

There is probably no point in signing up if you don't have an institutional email yet ;)

Maybe trillions, who knows

@Danu do you still studying at the university?

@Danu are you still studying at the university? (instead)

he's a grad student, yes

@AccidentalFourierTransform in theoritical physics?

mathematical physics

@AccidentalFourierTransform ah is it a good branch to specialise in?

no

why so ?

@AccidentalFourierTransform hahaha

;-)

It's the best branch! Nowadays I do pure mathematics though.

he is here

shhshsh !!!

lol

@JohnRennie : Indeed a masterpiece.

but mathematical physics branch related to mathematics

isn't it?

Sort of, but more related to physics.

mathematical physics is about the mathematics of physics

pure mathematics is just about mathematics

however i know a one student was specialised in mathematics and finally he chose applied maths with works more on physics

which works

tell me. what is the difference between applied maths and mathematical physics ?

@Student404Mus physicsforums.com/threads/…

@JaimeGallego ok

thanks

Just heard a talk about spider silk.

Spectroscopic study of composition of recluse spider silk.

Unsurprisingly, it's an organic polymer.

Interestingly, it's anisotropic.

WHY IS IT SO STRONG

(I heard spider silk is supposed to be strong)

Also, why study this?

Also, doesn't it make sense if it's anisotropic, given that it's supposed to be thread-like?

can anybody recommend a good lecture series on Electrodynamics

im gonna be reading burned out for a bit from other projects this week and want to try and follow along with material i need to review another way

~2nd half of griffiths

@Danu yes, it makes sense.

@Danu because nature tries stuff and literally kills the weakest trials ;-)

@Danu I don't know.

@DanielSank hello =)

twitch.tv/twitchpresents

@heather hi! I'm in New Orleans for the APS March meeting.

whoa, awesome!

I never saw power rangers before. That's one dumb show! :-)

how goes it?

Quantum computing and spider silk!

@Danu yeah, it's silly.

could i ask you a question? (if you're busy, I don't want to bother)

ACuriousMind made me realize that there's a pretty large flaw in my code, especially in how I work with control and target qubits, but I'm not sure how to remedy it, or what the proper way of calculating it looks like.

For example, if you apply a Hadamard gate to the first qubit, and then a cnot gate where the first qubit is a control-not gate, my code would say that the first qubit stays the same (which it does) and the second qubit is in the one state (it should be in the same state as the first qubit). I just now tried to understand by doing the calculation on paper (ACM said it need to be the full state of the whole system I manipulate) but I got the same incorrect answer.

so what would be the calculation to find the state of the control and target qubit, when the first qubit has the Hadmard gate applied to it, and then is the control qubit in a cNOT gate?

@heather you're using 4x4 matrices, right?

@DanielSank well, the calculation I did was the zero state [0,1] times the hadamard gate [[1/sqrt(2), 1/sqrt(2)],[1/sqrt(2),-1/sqrt(2)]], which gave me [1/sqrt(2), -1/sqrt(2)], and then the cnot matrix [[1,0,0,0],[0,1,0,0],[0,0,0,1],[0,0,1,0]] times the vector [1/sqrt(2),-1/sqrt(2), 0, 1] which gave me [1/sqrt(2),-1/sqrt(2), 1, 0]

i didn't really know how to just apply the hadamard gate to the first qubit using 4x4 matrices.

I think I see your error but I'm on my phone.

Will look later

@heather, do you still need help?

@DanielSank okay, thank you

@BuddyJohn if you're willing, yep =)

First,what do the numbers in your vector [1/sqrt(2),-1/sqrt(2), 0, 1] mean to you?

Or, alternatively, what would the vector look like if the system was in state |00> ?

well, in my mind, it means that the second qubit is in the zero state, and the other qubit is in the state 1/sqrt(2)|0>-1/sqrt(2)|1>

ah, okay. that is the problem

we can't really talk about the state of individual qubits, unless they are in a product state

which, since you want to do some quantum computing, will not usually be the case

i don't know how to think of them "together" i guess. how do you apply the hadamard gate to both qubits, when you only want it to affect one?

each qubit has two basis states, so for N qubits together there will be 2^N states

we can just label them with a string of 1 and 0

like for two qubits, you have 00, 01, 10, and 11

so for two qubits we have states: 00 , 01, 10, 11

yes, you beat me to it

three qubits: 000, 100, 010, 001, 110, 011, 111

no, that's one short

ah, I missed 101

well, in my case, i have two qubits.

how do I apply a hadamard gate to the first without "separating" the two qubits?

first, let's choose some order. And then the state vector is the coefficient for each of those basis states.

the order you wrote above sounds good

so [1,0,0,0] would mean the system is in state 00

okay.

that makes sense.

So if you want the hadamard gate to work on the first qubit, which two system states will it mix?

(err... I guess I meant, assuming you start in state 00)