Yeah this is like the only explanation of quantum computers that makes sense. Like why would I want to hear about someone murdering a cat when I could learn about THE SUBJECT I WAS TRYING TO LEARN ABOUT.
Must be so exciting to work on a groundbreaking technology! I’m glad there’s not a quiz after each video, but I will say I understand a qubit more than I did before. 😉
My friend, I am an undergrad doing research in Quantum Computing, specifically in circuit optimization, and your videos really gave me a wonderful insight into the hardware side of things, which I appreciate a lot. Thank you so much and keep up the beautiful work!!!
Hey Lukas, thank you so much for making this video! Your channel is going to grow really big in no time. I have some constructive feedback to make as I think this feedback will be useful for you if you don’t mind. In this particular video, there are two things that confuses me. The first is what is Anharmonicity and the second what is a Josephson Junction. The rest of the video addresses all my confusion regarding qubit. Thanks for making this video! On a related note, do you have books you can recommend regarding this topic?
Thanks for the feedback! I realized after posting that my audience wouldn’t have as much background as I initially thought - so my future vids will be better in this regard. For reference anharmonicity basically means changing the potential energy away from the simple harmonic oscillator potential so that energy levels aren’t perfectly evenly spaced out, and a Josephson junction (JJ) is a type of nonlinear inductor. If you put a JJ in an LC circuit instead of a normal inductor, you get an anharmonic energy spectrum that’s better for making qubits.
As for books - a good textbook would be Nielsen and Chuang, I’d also say read some nature papers on quantum computing because they are the most digestible. if you’re looking for a lighter read than those, cause getting through those is hard I’d say go to IBM’s online resources. They have some great stuff out there.
@@Lukas-Lab Thank you very much for the recommendation! I just bought the book and will definitely check out the IBM resources. I have tried their qiskit before and its great
1:33 lol watching that little dot go through thr inductor made it click. It causes lag because the electromagnetic field generated in the coil decreases flow of electrons
I have trouble walking & breathing at the same time, much less understanding this, but by God, I’m going to remain in the classroom, anyway!! 😤 Humph!!
Ambient temperature superconductors would be great! But we would still need to cool superconducting qubits down to nearly absolute zero anyways - because thermal noise would always be an issue and cause decoherence. It would definitely help with the room temperature electronics though! I may actually do a video on this now that you bring it up :)
Very nice, thank you! One question though: in the LC circuit, what is playing the role analogous to the kinetic energy term in the ball-on-spring system? Is it like, idk, current squared over some constant, or, something else? (I’m not experienced with circuits)
The inductive term is usually described as “kinetic” in a sense. I believe This is because of its relationship to the canonically conjugate variables used in the construction of its Hamiltonian. If you want to read up more on what that last sentence means (idk your physics background) check out the Wikipedia page for canonically conjugate variables, and then check out articles on circuit quantum electrodynamics (the name given to the study of superconducting qubits).
I want to mention what was confusing for me, I don't know anything about quantum computing beforehand, except for the 'how to build a quantum computer' video. The animation of the weight on the spring is just so confusing, since potential and kinetic energy are visible. But the spring and the weight itself is sideways, and I did not notice it in the beginning making it even more confusing (1:12 - 1:21). You mention at 1:22 'so if we take a small step closer to quantum computers. if we arrive at that small step, we arrive at the LC circuit', which is honestly just a confusing sentence, even with context. The 'arrive at that small step' just makes it confusing, it just might be me. The inductor explained very rapid, which no good explanation how it works, it just works because magnetic fields. The same holds true for the capacitor, like maybe give examples how it works. It is just exampled too quickly to really understand how they work (1:38-1:55). I think putting a bit more time into explaining how the current changes how time is a harmonic osculating motion. It does not make sense without more context/time put into it (1:56). Why is the potential energy tying both harmonic osculators together? (2:20) The formulas are displayed very briefly, and kind of good explained, but maybe an example would do no harm (2:45). You explain 'if we want to go from the harmonic potential to an equation of motion, we can use the Hamiltonian', and after an explain that you can do it differently, but you then mention that you use the Hamiltonian because the Hamiltonian translates most directly and naturally with quantum computers. But maybe you should first mention that you are going to go from harmonic potential to an equation of motion, to finally get the Hamiltonian, which is the sum of potential and kinetic energy. And then explain that you could have learned it in school but by balancing out forces, called Newton laws. There is no deep explanation why the Hamiltonian translates most directly and naturally with quantum computers, you also mentioned this in the video. But it is good that the examples are given. -Hamiltonian becomes an operator. How do we know the wave function? (4:18) And can't we use integrals to calculate it, or is that is how it's done? Because that is what the picture shows. And am I correct that the bloch sphere works with quaternions? (4:23) What do you mean with not all energies are allowed? (4:53) The 0 and 1 state, the 0 state can be set to x (whatever we like, that is allowed) and 1 set to x whatever is allowed. So that the system also knows the difference between 0 and 1. Is that correct, if not could you elaborate? The explanation of making a circuit quantum is kind of vague, since the temperature is not mentioned, and it hardly visible, except if you look for it. And the explanation is way too vague (5:35-5:57). The part about replacing a conductor with superconductor was explain well, just the part after that was ... vague. After that explanation we don't get a comparison between LC circuit and quantum LC circuit. (6:00) Which makes me think, do the LC circuit and the quantum LC circuit look the same? The explanation of how the energy between state 0/1 and 1/2 should be different because of stimulated emission, which makes you able to jump up or down depending on what state you are. Because of the energy difference (transitioning frequency) difference was at this point still the same. Correct? So, because you have different transitioning frequency between each state, it is a qubit? (8:00) What is special about the transmon qubit. How difference it from other qubits? I assume another architecture like mentioned in the previous video. And what are the benefits for it? The explanation of capacitive coupling is explained well but maybe an example (like how a relay works), could like to make it more visual. But I assume I understand what it does correctly. (It kind of reminds me of transformers for some reason) (9:40). Thanks for making these kinds of video's, they are really interesting. Sorry for writing a whole book.
Thanks so much for the detailed feedback! I’ll keep this in mind - I definitely didn’t give enough background on this video, so the next one will have some better structure.
So I'm working my ass off trying to present an academic seminar on the mathematics behind quantum computing bro i need to know how did you get yo know all that
