I do think part of the explanation at. Is good thoigh..when she says the bomb measures the photon, that's not true..it will only.measure if the photon passes through thst oath in the beam splitter and hits the bomb..otherwise the bomb will not measure it..and how does the bomb exploding clause the wabefuncfion..it wouldn't the part of the photon thst went through the other oath would still be there..or if it'd just a probability then it could still be tbere..a bomb is not a measuring device after all..
Fascinating, a new phenomena for me. I also hadn’t heard of the quantum Zeno effect and don’t really follow its role in affecting the probabilities, but I’ll look for some vids on that effect by itself
Glad you liked the video, we now have one on the quantum Zeno effect too! ua-cam.com/video/vfUn8cR-eXw/v-deo.html. In the bomb tester, the Zeno effect means that if the photon is "measured" by the bomb every time it passes through the beam-splitter, the superposition state does not evolve and remains how it was at the beginning with high probability, and is likely reflected at the end. If there is no bomb, there is no measurement to cause the Zeno effect, and the photon's state evolves as it goes through the beam-splitters until it is definitely transmitted at the end, so we can distinguish the two cases.
Representing the bomb as a qubit sounds unclear to me. The qubit is a quantum object whereas the bomb is not. In the sense that , the photon state collapse when it interact with the bomb but it doesnt collapse when interacting with another qubit. The Quantum circuit is not correct. The bomb should be represented as a measurement I think.
Exactly and do you agree hwne she says the bomb.meadures the phktonthst is inaccurate..a bomb is not a measurement device so it can't or won't collpase the photon..
This is a subtle point! I'll copy my reply for a similar comment here: "Yes instead of the CNOT with the bomb qubit, we could have added a mid-circuit measurement between the Hadamard gates, modelling the bomb as the classical "bit" that stores that measurement outcome (which can be unexploded 0 or exploded 1) instead of a qubit. We would get the same distribution of measurement outcomes with such a "classical bomb" that causes an irreversible wave function collapse and a "quantum bomb" that becomes coherently entangled with the photon. My preference is to model the bomb as a quantum system, i.e. as a qubit instead of a bit, one reason being that the conclusions can then apply for all scales (e.g. if we replace the bomb with an atom)." Whether a bomb is genuinely a quantum object or a classical one is up for debate, but I believe most quantum scientists would agree that a bomb that is completely isolated from its environment would behave as a quantum object. Currently we are not able to isolate large objects like bombs from their environment, although the whole challenge of quantum computing is to achieve this kind of isolation for a very large number of qubits, to maintain quantum control over them before they decohere.
Thanks for the video! Very clear. One question: In the histogram of the simulated quantum computer result at 6:00, we have states (00), (01), (10), (11), where the bomb state is represented by the number on the left in the parentheses, and the photon state is on the right. I see how the circuit would produce this outcome, but it is a bit puzzling to me for the cases (10) and (11), for which the bomb has detected the photon. If the photon has been absorbed by the bomb sensor in both of these cases, what is the meaning of the photon states 0 or 1 in these histogram entries, given that there is zero probability of the photon being detected at the exit of the interferometer?
CORRECTION AT 312 the photon could either be REFLECT OR TRANSMITTED at the second beam splitter and. EITHER WAY is possible and would tell you the bomb was tbere..since it went on the second path thst was collpased..anyone else catch this mistake?
Only the case where the photon is reflected at the second beam-splitter tells you that the bomb was there for sure. This is because, if there is no bomb, then the photon will definitely be transmitted. So if the bomb collapses the photon to the second path, and the photon is transmitted at the second beam-splitter, there's no way to tell the difference between that and the case with no bomb. Hence it gives an inconclusive outcome.
How many times can a photon be split and if there is a defined moment when it can no longer be split, what is the amount of energy within the supposed “Base Photon”? If it shows a disintegration of energy at the base, does that mean energy is being lost while measuring it? It seems we’re missing something as we measure. Are we measuring a depleted energy source or the supposed base photon energy source that has been divided?
No energy is lost as the photon splits, and the photon could be split any number of times. For example, let's say we are in the branch where the photon was absorbed by the bomb and the bomb exploded. The energy of the photon before it was split is exactly the same as the energy the photon has when it is absorbed by the bomb. The other part of the overall superposition also has a photon with the same energy as before it was split. This is counter-intuitive: it might seem that the energy of the original photon has been doubled when it splits at the beam-splitter. But, because each part of the superposition has a 50% weighting, when we work out the total energy, it is the same before and after the photon was split.
Hi Maria. There may be in certain circles the opinion about publishing this sort of thing " Does everybody have to know ?". Apart from the possibility of this being extended as a universal lost property finder or a universal solver for mathematical expressions including the Clay Maths challenges the application space is infinite. One more application. "missing persons finder".
For the circuit at 5:37, couldn't its results be explained if the wavefunction collapses at the CNOT gate? Is there any reason why that can't be what's happening?
Yes instead of the CNOT with the bomb qubit, we could have added a mid-circuit measurement between the Hadamard gates, modelling the bomb as the classical "bit" that stores that measurement outcome (which can be unexploded 0 or exploded 1) instead of a qubit. We would get the same distribution of measurement outcomes with such a "classical bomb" that causes an irreversible wave function collapse and a "quantum bomb" that becomes coherently entangled with the photon. My preference is to model the bomb as a quantum system, i.e. as a qubit instead of a bit, one reason being that the conclusions can then apply for all scales (e.g. if we replace the bomb with an atom).
Hi Maria is a pleasure to meet you. My name is Alberto from Venezuela. Does it seem like as Stern-Gerlach experiments when the photon is separating by splitting device? Well-done video and go ahead in your Ph.D. studies wishing to you all the best.
Glad you liked the video! In the standard Stern-Gerlach experiment, a particle in a superposition of two spin states is put into the magnetic field, and the magnetic field acts as a "measurement device" projecting the particle into one direction of spin or the other, so the particle moves in different directions depending on the spin it is projected into. So the magnetic field in the Stern-Gerlach experiment is like a measurement device (so, like the bomb and detectors), and the particle that goes in to the device is already split into a superposition (like the photon after the beam-splitter). Hope that helps!
But it's about without actually interacting with the box , so may be you can't do in that way. Although we are using the bomb or qubit itself to detect it. But it's indirect.
The idea is that this highly-sensitive bomb will explode if absolutely any particle interacts with it, including particles in your hand. We just tend to use the photon as an illustrative example!
quantum mechanics Fs up the causality which is a extraordinary claim which needs real world proof i'm not saying it is false it just needs to be tested to make sure there is some unknown dynamic in physics which we didn't knew was there to complete causality. Because without causality lots of paradoxes appear.
Great video, I especially like the Qiskit application. On an unrelated note, I've never heard an accent where "photon" was pronounced as "FAY-ton". Can you tell me where your accent is from?
She kept calling a zero a knot, I was like a knot? Then I realized she was saying naught instead of zero and she kept using both zero and naught and it was a little confusing at first. 😂
3:16 You say you can work out if the bomb is there without it exploding with up to a 100% chance. I dont see how you can do that. Maybe 99.999999999% chance but 100%?
Yes I really meant, "up to (but not including) a 100% chance". You can get as close to 100% as you like by adding more beamsplitters of higher reflectivity, though you can never reach exactly 100%. Hope that clarifies things!
Excellent explanation. Keep up the good work. Good luck with your dissertation.
I do think part of the explanation at. Is good thoigh..when she says the bomb measures the photon, that's not true..it will only.measure if the photon passes through thst oath in the beam splitter and hits the bomb..otherwise the bomb will not measure it..and how does the bomb exploding clause the wabefuncfion..it wouldn't the part of the photon thst went through the other oath would still be there..or if it'd just a probability then it could still be tbere..a bomb is not a measuring device after all..
Great explanation of an interesting quantum phenomenon!
Fascinating, a new phenomena for me. I also hadn’t heard of the quantum Zeno effect and don’t really follow its role in affecting the probabilities, but I’ll look for some vids on that effect by itself
Glad you liked the video, we now have one on the quantum Zeno effect too! ua-cam.com/video/vfUn8cR-eXw/v-deo.html. In the bomb tester, the Zeno effect means that if the photon is "measured" by the bomb every time it passes through the beam-splitter, the superposition state does not evolve and remains how it was at the beginning with high probability, and is likely reflected at the end. If there is no bomb, there is no measurement to cause the Zeno effect, and the photon's state evolves as it goes through the beam-splitters until it is definitely transmitted at the end, so we can distinguish the two cases.
Nice application of quantum computers, keep it up 👍
Thanks, a very interesting experiment.
I look forward to the next one.
Great work Maraki!
Great explanation! Thanks a lot !!!
Nice Explanation, Thanks
Representing the bomb as a qubit sounds unclear to me. The qubit is a quantum object whereas the bomb is not. In the sense that , the photon state collapse when it interact with the bomb but it doesnt collapse when interacting with another qubit. The Quantum circuit is not correct. The bomb should be represented as a measurement I think.
Exactly and do you agree hwne she says the bomb.meadures the phktonthst is inaccurate..a bomb is not a measurement device so it can't or won't collpase the photon..
This is a subtle point! I'll copy my reply for a similar comment here: "Yes instead of the CNOT with the bomb qubit, we could have added a mid-circuit measurement between the Hadamard gates, modelling the bomb as the classical "bit" that stores that measurement outcome (which can be unexploded 0 or exploded 1) instead of a qubit. We would get the same distribution of measurement outcomes with such a "classical bomb" that causes an irreversible wave function collapse and a "quantum bomb" that becomes coherently entangled with the photon. My preference is to model the bomb as a quantum system, i.e. as a qubit instead of a bit, one reason being that the conclusions can then apply for all scales (e.g. if we replace the bomb with an atom)."
Whether a bomb is genuinely a quantum object or a classical one is up for debate, but I believe most quantum scientists would agree that a bomb that is completely isolated from its environment would behave as a quantum object. Currently we are not able to isolate large objects like bombs from their environment, although the whole challenge of quantum computing is to achieve this kind of isolation for a very large number of qubits, to maintain quantum control over them before they decohere.
Thanks for the video! Very clear. One question: In the histogram of the simulated quantum computer result at 6:00, we have states (00), (01), (10), (11), where the bomb state is represented by the number on the left in the parentheses, and the photon state is on the right. I see how the circuit would produce this outcome, but it is a bit puzzling to me for the cases (10) and (11), for which the bomb has detected the photon. If the photon has been absorbed by the bomb sensor in both of these cases, what is the meaning of the photon states 0 or 1 in these histogram entries, given that there is zero probability of the photon being detected at the exit of the interferometer?
CORRECTION AT 312 the photon could either be REFLECT OR TRANSMITTED at the second beam splitter and. EITHER WAY is possible and would tell you the bomb was tbere..since it went on the second path thst was collpased..anyone else catch this mistake?
Yes
Only the case where the photon is reflected at the second beam-splitter tells you that the bomb was there for sure. This is because, if there is no bomb, then the photon will definitely be transmitted. So if the bomb collapses the photon to the second path, and the photon is transmitted at the second beam-splitter, there's no way to tell the difference between that and the case with no bomb. Hence it gives an inconclusive outcome.
great work
The concept is awesome but the explanation for the second and third part is bit too short. Thanks!
This is very good
How many times can a photon be split and if there is a defined moment when it can no longer be split, what is the amount of energy within the supposed “Base Photon”? If it shows a disintegration of energy at the base, does that mean energy is being lost while measuring it?
It seems we’re missing something as we measure. Are we measuring a depleted energy source or the supposed base photon energy source that has been divided?
No energy is lost as the photon splits, and the photon could be split any number of times. For example, let's say we are in the branch where the photon was absorbed by the bomb and the bomb exploded. The energy of the photon before it was split is exactly the same as the energy the photon has when it is absorbed by the bomb. The other part of the overall superposition also has a photon with the same energy as before it was split. This is counter-intuitive: it might seem that the energy of the original photon has been doubled when it splits at the beam-splitter. But, because each part of the superposition has a 50% weighting, when we work out the total energy, it is the same before and after the photon was split.
This go hard yo. Spooky 🎃
Hi Maria. There may be in certain circles the opinion about publishing this sort of thing " Does everybody have to know ?". Apart from the possibility of this being extended as a universal lost property finder or a universal solver for mathematical expressions including the Clay Maths challenges the application space is infinite. One more application. "missing persons finder".
For the circuit at 5:37, couldn't its results be explained if the wavefunction collapses at the CNOT gate? Is there any reason why that can't be what's happening?
Yes instead of the CNOT with the bomb qubit, we could have added a mid-circuit measurement between the Hadamard gates, modelling the bomb as the classical "bit" that stores that measurement outcome (which can be unexploded 0 or exploded 1) instead of a qubit. We would get the same distribution of measurement outcomes with such a "classical bomb" that causes an irreversible wave function collapse and a "quantum bomb" that becomes coherently entangled with the photon. My preference is to model the bomb as a quantum system, i.e. as a qubit instead of a bit, one reason being that the conclusions can then apply for all scales (e.g. if we replace the bomb with an atom).
Hi Maria is a pleasure to meet you. My name is Alberto from Venezuela. Does it seem like as Stern-Gerlach experiments when the photon is separating by splitting device? Well-done video and go ahead in your Ph.D. studies wishing to you all the best.
Glad you liked the video! In the standard Stern-Gerlach experiment, a particle in a superposition of two spin states is put into the magnetic field, and the magnetic field acts as a "measurement device" projecting the particle into one direction of spin or the other, so the particle moves in different directions depending on the spin it is projected into. So the magnetic field in the Stern-Gerlach experiment is like a measurement device (so, like the bomb and detectors), and the particle that goes in to the device is already split into a superposition (like the photon after the beam-splitter). Hope that helps!
I am very grateful for your reply and you are showing your passion for Quantum Computing@@maria_violaris. I am wishing to you all the best .
What the heck is a Phaiton ?
can't I just take the box in a blacked-out room - like photon-less - and open it, dig around with my hands and determine this directly?
But it's about without actually interacting with the box , so may be you can't do in that way. Although we are using the bomb or qubit itself to detect it. But it's indirect.
The idea is that this highly-sensitive bomb will explode if absolutely any particle interacts with it, including particles in your hand. We just tend to use the photon as an illustrative example!
Assuming that there's something "like a particle" passing through the beam splitters is misleading
Yes..
fun!!! Fun!!!
quantum mechanics Fs up the causality which is a extraordinary claim which needs real world proof i'm not saying it is false it just needs to be tested to make sure there is some unknown dynamic in physics which we didn't knew was there to complete causality. Because without causality lots of paradoxes appear.
This was my idea originally...
Great video, I especially like the Qiskit application.
On an unrelated note, I've never heard an accent where "photon" was pronounced as "FAY-ton". Can you tell me where your accent is from?
Quantum mechanics >>>>> anime xD
Rebecca?
Another person who doesn't understand quantum mechanics. ;-)
It's photon , not phaeton .... I'm done with Bri 'ish accent
Keep crying about it
She kept calling a zero a knot, I was like a knot? Then I realized she was saying naught instead of zero and she kept using both zero and naught and it was a little confusing at first. 😂
Phouton!!
I think we should have the cats do this experiment for us, there will be a higher probability of the experimentor coming back to relay its result.😉
3:16 You say you can work out if the bomb is there without it exploding with up to a 100% chance. I dont see how you can do that. Maybe 99.999999999% chance but 100%?
Yes I really meant, "up to (but not including) a 100% chance". You can get as close to 100% as you like by adding more beamsplitters of higher reflectivity, though you can never reach exactly 100%. Hope that clarifies things!