Just watched this with the whole team, thanks for featuring this! 💎
And simply amazing how you condensed such a complex topic into 17mins!
Quantum_Diamonds
I need to wrap my head in duct tape to keep it from exploding.
nopenotme
I love that quantum sensing is becoming more "mainstream". I work on quantum networking, but a big part of selling that is showing that other things can also be done with quantum networks such as, you guessed it, various quantum sensing applications.
Edit: I just wanted to add a small correction to your analogy @5:50 . Extending coherence isn't exactly like noise cancelling headphones since they actively mitigate outside noise. The "dynamic decoupling" you mentioned is more of a "photon echo" effect. Imagine a bunch of racers of various speeds lined up on the starting line in perfect coherence. The starting gun fires and they're off. The fastest ones go further and the slowest travel the least, slowly decohering as time progresses and the slowest and fastest of the group get further and further apart. To fix this, periodically you have the starting gun fired again and have everyone turn around and run the other way. The fastest of the group have longer to travel, but they're moving quicker so they make up the extra distance. By the time everyone gets back to the starting line, everyone is roughly lined back up and in coherence again
twilightknight
I actually designed, built, and tested a cryogenic system to do these types of NMR experiments, and I used these types of spectroscopy synthetic diamond NV centers to validate it! Very cool to see a video on your channel about it :)
matfclips
Honestly one of the best explanation of spin I’ve seen.
qtheplatypus
Man this is a great channel how am I just NOW finding this?
CTSkydives
This is what I understood at a very general level from the video, if anybody see conceptual errors, please comment it out so we can get a more accurate version.
Diamonds are a bunch of Carbon atoms in a special configuration (a three dimensional shape), which we're going to call CC. If in the CC configuration, a Carbon atom is replaced by a Nitrogen atom and another neighboring Carbon atom is removed (creating a vacancy, i.e. the absence of the Carbon atom that normally occupies that place in the CC configuration), then another special configuration called NV (Nitrogen-Vacancy) is created. In turn, that NV configuration has different sub-configurations, depending on the electrons it is having. The one that matters is when the NV configuration has 6 electrons, which gives it a net negative charge. I'm going to call this sub-configuration the NV6 configuration.
A small digression, an electron has a special property called spin (we can think of that property as the "colors" of the electron). Now, that property can only take a fixed and predefined set of values (for example green, black, blue, red and yellow). That is why it is said that this property is quantized. Interestingly, we can measure the spin of an electron and also operate on the electron to change its spin.
It is said that there is coherence when we can operate, that is, manipulate the spin of a set of electrons in such a way that it is possible to pass from one state (i..e. the set of spin values that each of those electrons has at that moment), to another state in a predictable and reversible way (that is, I can reverse the applied operation so that I can obtain the original state). This is usually possible for extremely short times, since these electron systems are very sensitive to any type of interference, which makes the result of the operation neither predictable nor reversible. Not having coherence is like having a calculator where I perform an operation, and the results are random, in that case the calculator is useless to me, I can't perform operations on it, which is the ultimate goal of a calculator.
Well, it turns out that the electrons of the NV6 configuration form a coherent system at room temperature, that is, they work like a calculator, in the sense that I can do operations on them at room temperature, and the results are predictable and reversible (I can undo the operation by returning to the original result). Additionally they behave like a calculator in that they have a "screen" that allow me to observe the result of my operation in a "simple" way. The "screen" of this atomic calculator is that as it is changing of state, the atomic calculator is emitting a fluorescence that varies with the result of the operation (i.e., by measuring the variation of the fluorescence that the atomic calculator emits, I can know the result of the operation). In short, what I have now is a viable atomic-sized a calculator that is possible to operate at normal temperatures ("room temperatures").
Well, I have that mini atomic calculator that occurs in a natural way, but I have to solve several problems to be able to use it in any meaningful way:
(1). Calculation power: if I have a single NV6, I only have 6 electrons to perform my operation, that's very little. I need a lot of them
(2). Layout: I have to be able to group many NV6 so that they are close to each other, so that the operation affects them all, and also they have to be close to the surface, so as to use as little energy as possible in the operation.
(3). Manufacturing: in a natural diamond, the NV6 configuration occurs randomly, so, it is extremely unlikely that it will be produced in such a way as to solve problems 1 and 2. Therefore, the only way to resolve the problems 1 and 2 is through manufacturing. It is necessary to manufacture synthetic diamonds with the NV6 configuration that solve problems 1 and 2. But since we are talking about nano-scale, we have to use the technologies that are used to create the current chips, to create a diamond chip with NV6 configurations that solve problems 1 and 2.
(4). Operation mechanism: finally, even if I have a diamond chip that offers me a powerful atomic calculator that works at normal temperature, I need to implement on this some kind of mechanism that allows me to perform operations on it and read its result. A special operation is to use the diamond chip as a sensor, and the mechanism to be used is that this chip is predictably sensitive to a magnetic field, that is, the values on the "screen" of that diamond chip, atomic calculator, change predictably with the variations of the electromagnetic field (e.g. moving a magnet closer or further away). The way to use it is as follows, I expose the diamond chip to a magnetic field, and I get a certain value on the "screen". Now, I move the diamond chip closer to a sample, for example a human tissue, and I emit the same magnetic field again, now, this magnetic field is going to be modified by the sample, so my diamond chip is going to receive a magnetic field different from the original, and therefore it is going to produce a different value in its "screen", the difference between the original and the current value allows me in turn to infer properties of the sample, but with a sensitivity at the atomic level, that is, I can now measure properties of the sample at atomic levels, which gives me a gigantic level of detail.
Finally, the reason for the title, it is called quantum sensing, because it is being used a sensor at the atomic scale (my atomic calculator or diamond chip), and everything that operates at that scale is governed by the laws of Quantum Mechanics. i.e., the possible values that the spin of an electron takes and the way it changes state is governed by Quantum Mechanics, not the Einsteinian or Newtonian mechanics.
huveja
"Nitrogen vacancy centered diamonds are a girl's best friend"....m'ais naturellement!
stevengill
8:07 - I went to high school with David DiVincenzo back in the 1970s. The guy was the smartest person in our graduating class, from a prep high school that attracted top students. No surprise he became a brilliant scientist.
stevebabiak
What I'm lost on is how MPCVD can maintain periodicity of the defects. That sounds astronomically difficult, if not outright impossible.
me
It's really refreshing seeing DiVincenzo's paper here, that was the beginning of spin qubit.
fsdds
I think I only understood 10% of what he said, but it's a beginning. I love that he covers this bleeding edge tech, but with a certain sarcasm at the tech buzz words.
skyblueo
I was just quickly going through a paper with the author about this topic less than 2 weeks ago. It's insane. Thank you for bringing this topic to the forefront!
raindropsrising
Great video, as always.
Made me smile to see Espoo, Finland mentioned, as I have many happy memories from my semiconductor days there.
alansillitoNYC
my brain starts smoking with some of your videos man : )
marcussassan
You can see a few of these effects in a rudimentary way yourself with a cheap, zwb2 filtered 365nm ultraviolet flashlight. Many natural diamonds, and virtually all synthetic HPHT and CVD diamonds have lattice defects of some kind or another and the electrons trapped at these defects DO flip their spin when bumped into an excited state by the UV excitation. Because the electrons cannot relax back to the ground state without first flipping their spin again (forbidden transitions), they have to wait until a phonon of lattice vibration comes along and spontaneously flips the spin. Because this takes significant amounts of time in the very stiff lattice of diamond, as mentioned, the crystal will glow in the dark for many seconds after the UV light is shone on it - phosphorescence.
Muonium
Now I see why some developers are using light, rather than electrons, for Quantum Computing Hardware. Angstrom's of light, and physical reflectors do not need cold, expensive environments, or clumsy magnets. Angstrom measures are a lot smaller than the Nano-Metre scale.
Twisted Field Transistors (like the monitor you are now looking at) make for tiny, fast switching mirrors and filters. Light is a lot easily to shield than Electro-magnetic fields. We already have the science to emit a single photon, on command.
cinemaipswich
Chief Quantum AI blockchain researcher here:
I did not appreciate the intro. 😆
nellyx
You make these advanced topics understandable - thanks.
kenfenske
So many great well researched high quality videos, well done mate!
