The Language of Quantum Physics is Strange | PHYSICS EXPLAINED

This is how Quantum Physicists communicate their ideas

Hi guys, so I wanted to make a video explaining some of the notation used by quantum physicists to describe their ideas. There is a reason why things are written the way they are, and it is interesting to see these reasons, in my opinion.

In the video we will see bra and ket notation, originally invented by Paul Dirac, which is used describe the wave function of a quantum state - essentially all the mathematical information we know about our quantum system, which is the part of the universe we happen to be studying.

Bra-ket notation uses a ket to represent a quantum state, with the ket being distinct from, but mathematically related to, the bra. The ket representing a quantum state can also be written as a superposition of possible results to a measurement. For example if our system is an electron, and we measure its spin, then the electron's state BEFORE we measure its spin can be written as a superposition of the possible results of a spin measurement - spin up and spin down. This superposition is mathematically written by adding states together. The numbers in front of each state are directly related to the probability of us finding our system in that state, upon measuring.

AFTER we make a measurement, the system collapses into ONE of the possible measurement results - we never actually find it to be in a superposition. There are other subtle effects that tell us that a quantum system can exist in a superposition of states, but upon measurement the system probabilistically collapses into one of the possible measurement result states. This is called the Collapse of the Wave Function.

We also see that quantum states can be very nicely described by vectors in an abstract mathematical space known as a Hilbert Space. The quantum states display certain mathematical behaviours that are very similar to those displayed by vectors in real space. Additionally, we can use the Hilbert Space to represent the state of any quantum system, even one in a superposition of states, with one single vector. Pretty neat right?

Now guys I know that there's a lot of background noise in this video - I'm really sorry about this, but after all I live with my family and they have every right to speak in their own homes lol. Next time I'll try to find a time when there isn't as much going on in the background, to make a video.

Let me know what kind of videos you want to see from me next!

Follow me on Instagram @parthvlogs - I'm going to be posting a couple of IGTV vlogs on there towards the end of the year. Until the next video, see you soon!

[hemangmathur]

That illustration of schrodigers cat at 3:00 is the best thing I've seen all day.

[crinanthethane]

Please don’t change anything regarding your content and style. Your explanations, for a truly complex topic, are easily digested for this simpleton. Much love & respect! 😁🙏🏼

[kassios]

Wow, I actually understood everything!
Looks like my Linear Algebra university lessons weren't useless after all. (Matrixes are everywhere)...
You sir are an excellent teacher.

[clint]

seriously loved this! i now get the wave equation notation like never before!! I'm an electrical engineer by degree and I work for NASA JPL and I've studied quantum mechanics a bit for particle accelerator and plasma physics work that I do but the math for QM hadn't quite clicked for me until you just explained it in the 2d space similar to the unit circle for complex math! GREAT video! and i hadn't known about the ket and bra and bra-ket lol thanks! i really like all of your videos! please keep it up!

[perpetual_bias]

This has been _extremely_ eye-opening. Thank you

[arunjanarthanan]

Within the fist 2 seconds of the video beginning, I start smiling, and feel as if you have already conveyed the key point! transfer of knowledge at its beautiful best!

[Lostmemarbles]

Wow, I've never made a Youtube comment. I'm a fan after one video! Thank you for making understandable videos on a complex subject. Great work! Now I'll never get any

[ianbolton]

Excellent... I studied this 30 years ago as an undergrad and it brings it all back. Very clear and I agreed with the another persons comment that more of this stuff needs to be explained and taught to 16 to 18 year olds; this video helps make it accessible.

[stevemetcalf]

Just the kind of level I am looking for. I'm a retired 69 year old just discovering quantum theory and love everyone of your videos. The comments section is also very entertaining, and at times controversial. But what would physics be without some challenges? Keep up the good work sir, you are an inspiration.

[xfoxawy]

u just explain it as simple as possible which is amazing
keep it up my man

[cybrainx]

You are one of those no-nonsense youtuber :) Thanks for making this.

[mushtaqhussain]

Sir you are far better than most of our nonsense proffesors who themselves dont know what are they teaching.
Thank you for all of these conceptuall stuff you are delivering ❤

[paulnelson]

Damn im studying applied mathematics and this video was truely brilliant, the way you described shrodinger equation was awsome keep up the good work
Wish u luck

[bineshpv]

I am 38 now .... I still want to learn QM in depth. I realise that you could help me in suggesting the correct references in addition to watching your videos... you explain everything very nicely..excellent job...keep it up.

[HaiderKhan-ncgf]

My dear Parth you are a blessing. Because you explain every little thing from the very basics. Not many are doing that with such clarity and eloquence as you do. Thanks

[littlemermaid]

Hey Parth! I can’t thank you enough for this... For once quantum physics started making sense to me .. I used to love physics until it all seemed getting so abstract and complicated, I lost it completely .. I have been a housewife for past 6 years and you make me think of getting back to studying physics. I watch your physics videos in my free time..
I have a request for you.. Is it possible to make a video on evolution of physics ? How different fields of physics came into being?

[olversevilla]

Great video, honestly the spirituality thing and Quantum mechanics are so realted, that's why 2 things can exist at the same time and at the same place.

[CrownedMeadow]

You have such a uniquely-natural and logical way of explaining these very supernatural, illogical phenomena. Keep it up. 👍

[brendanfan]

This is the best channel that can explain the foundamental ideas of physics so well. Highly recommended.

[adinathkolhapure]

"How to do higher studies in quantum physics and what is scope" please make a video about this 🙏