Quantum 101 Episode 8: Photoelectric Effect Explained

Digital cameras, small enough to be embedded in our phones, have transformed photography and changed how we interact with the world and each other.
But did you know that this sophisticated piece of modern technology has its roots in the science that won Einstein a Nobel Prize?
Most smartphones today use a sensor called a complementary metal oxide semiconductor or CMOS. It's similar to a CCD or charge coupled device and works because of this one weird trick physicist discovered more than a century ago.
This video discusses how quantum mechanics, once an esoteric flight of fancy, now plays a role everywhere we look.
Join Katie Mack, Perimeter Institute’s Hawking Chair in Cosmology and Science Communication, over 10 short forays into the weird, wonderful world of quantum science. Episodes are published weekly, subscribe to our channel so you don’t miss an update.
Want to learn more about quantum concepts? Visit perimeterinstitute.ca/quantum... to access free resources.
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[@mimidhof2179]

Wonderfull series, I want more please keep going on.

[@alpbaharcan]

Thank you for these episodes. Inspiring

[@cubeow1]

Best KZbin video explaining this effect

[@guyhouri7590]

Great video. Thank you ❤

[@zenbh4006]

Very helpful!

[@Roberto-REME]

Excellent video, Katie and great explanation of the photoelectric effect. I liked Damian's contribution as well, but I must say it was not Einstein who 1st thought of photons not just as waves but as physical packets. If I remember correctly it was Newton. First, Newton = light is made of small particles. 2nd: Thomas Young (1801) = light is a wave. 3rd. Einstein = light is quantized, but it's both a particle and a wave. Thank you for a great vide Katie and I wished you would do one on gravity not a force and the whole business of "...it's not pulling you down, rather the earth is rising." Love to hear your explanation of this phenomenon.

[@TheScentofmusic]

Such a nice and in an enthusiastic way of presentation. Such should be the presentations on explanations.

[@jacksourlis4151]

1. The apparent paradox that arises when trying to reconcile the wave function perspective with Einstein's well-established photoelectric effect theory. 2. The possibility that the wave function may simply not be a relevant or necessary consideration in explaining the photoelectric effect, which operates solely on the frequency-based principles. 3. How this could lend support to the MWI's assertion that the wave function does not actually collapse, since the wave function seems unnecessary for understanding a fundamental quantum phenomenon like the photoelectric effect. 4. The importance of critically examining the scope and limitations of the wave function concept, rather than automatically assuming its applicability to all quantum mechanical processes.

[@jacksourlis4151]

I call it the “Sourlis Implementation”… Combining the double-slit experiment with the photoelectric effect: Normally these are considered separate experimental setups, but merging them by using a metal plate instead of a standard detection screen is an innovative approach. The indirect observation of interference: Rather than directly observing the interference pattern on a screen, you are inferring it from the spatial distribution of the emitted photoelectrons/secondary electrons. This adds an extra layer of complexity. The delicate balance between wave and particle behavior: The ability to switch between observing interference (wave-like behavior) and obtaining "which-slit" information (particle-like behavior) by simply adding the detectors is a
quintessential demonstration of the wave-particle duality in quantum mechanics. The potential for new insights: This modified setup may provide additional insights into the fundamental principles governing the behavior of quantum particles and the measurement process. Exploring the interplay between interference, detection, and electron emission could lead to a deeper understanding into the: a) Wavefunction, as with no detectors in place behind the slits because of the wavefunction intensity will lead to higher emissions and thus provide insights or interpretation of the wavefunction by this intentional manipulation. b) It will reinforce superdeterminism and bohemian mechanics. c) The multiverse theory will have to be redefined. d) Potential Insights into Quantum Computing and Information: Understanding the relationship between wavefunction manipulation and quantum phenomena could have implications for the development of quantum technologies, such as quantum computing and quantum communication. And more And this is based on if the observed results match the standard quantum mechanical model, the very fact that we can intentionally control the wavefunction intensity to produce the anticipated outcomes could be seen as evidence supporting the principles of superdeterminism. The 3 scenarios of results are 1. Wavefunction Intensity play a role as this would be according to the standard Quantum Mechanical theory. 2. Wavefunction Intensity did not have an effect on results which would indicate something a miss with special relativity and that quantum mechanics would have to be redefined without the constraints placed on it by that of special relativity. 3. No emission from plate with detectors in behind the slits would indicate a misunderstanding by mainstream physics, and if this was the case i would suggest the next step would be to remove the slits while leaving the detectors and the full implementation of the rest of the dual experiments intact, and if further no emissions result then my theory which I have would be of some use (I don’t need to elaborate on my theory at this moment), this is what lead me to suggesting this implementation in the first place. (A further Note is that the two fundamental concepts of the speed of light being constant and that of entanglement being a byproduct would remain yet the Doppler effect would have to be revised). Overall, the integration of these two foundational quantum experiments has the potential to provide a more comprehensive picture of the wavefunction and its behavior, as well as shed light on the ongoing debate between deterministic and probabilistic interpretations of quantum mechanics, including the concept of superdeterminism.

[@jacksourlis4151]

The Sourlis Implementation Of the double-slit and photoelectric effect experiments: Apparatus: 1. Monochromatic light source (e.g., LED or low-power laser) with a photon energy just above the work function of the metal plate 2. Double slit apparatus 3. Metal plate (e.g., thin aluminum or copper foil) chosen to have a work function matched to the photon energy 4. Photoelectron detectors (e.g., microchannel plate detectors) placed behind each slit 5. Voltage source to apply a potential difference across the metal plate 6. Ammeter or picoammeter to measure the photoelectric current 7. Collimating optics (e.g., lenses, apertures) to control the beam shape and angle of incidence 8. Mounting hardware to securely hold the components in place 9. Case 2: Using electrons as the source 10. Apparatus: 11. Electron source (e.g., thermionic electron gun) with an energy just above the work function of the metal plate 12. Double slit apparatus 13. Metal plate (e.g., thin aluminum or copper foil) chosen to have a work function matched to the electron
energy 14. Electron detectors (e.g., microchannel plate detectors) placed behind each slit 15. Voltage source to apply a potential difference across the metal plate 16. Ammeter or picoammeter to measure the secondary electron current 17. Collimating and focusing optics (e.g., electrostatic or magnetic lenses) to control the electron beam 18. Vacuum chamber to maintain a high-vacuum environment 19. Mounting hardware to securely hold the components in place The key updates are: * Using a monochromatic light source or a low-energy electron source, just above the work function of the metal plate * Choosing the metal plate material to have a work function matched to the photon/electron energy * This ensures the photoelectric effect or secondary electron emission is induced, but without excessive energy that could complicate the experimental observations.

[@jacksourlis4151]

Regarding the multiverse or many worlds interpretation…the standard MWI predicts that the wavefunction should maintain its interference pattern and higher overall intensity, even with the presence of the slit detectors, since the wavefunction does not collapse according to this interpretation. However, the experimental findings show a lower wavefunction intensity when the detectors are in place, which appears to contradict the MWI's predictions. Overall, I believe the MWi can be further developed and combined with other quantum interpretations to provide a more comprehensive understanding of the complex dynamics at play in the combined double slit and photoelectric effect experiment. By exploring the selective amplification or "biasing" of wavefunction branches, as well as the role of decoherence and measurement interactions, the MWI may be able to be reconciled with the experimental observations. But a case could be made for the MWI whereas the other interpretations could not, and, that would be if no difference is made from the wavefunction intensity (meaning no change in emissions)… explained… Experiment result #2… The experiment shows no reduction in wavefunction intensity, even with the presence of detectors. * This would be a surprising result, as it would contradict the established experimental evidence. * If verified, it would lend strong support to the standard MWI and its prediction of the preservation of the full wavefunction and interference pattern. * It could undermine the current understanding of the role of measurement and decoherence in quantum mechanics. * This outcome would likely require a significant rethinking of how we model the interactions between quantum systems, measurement devices, and the environment. • It could lead to a major shift in the theoretical foundations of quantum mechanics, potentially favoring the MWI over other interpretations. But Einstein uses the frequency scale… The key paradox is: * According to Einstein's photoelectric effect, the electron emission and energy should be independent of light intensity. * However, the wave function intensity, which I've suggested impacts the probability of electron emissions, is proportional to light intensity. This creates an inherent contradiction - the photoelectric effect principles indicate no dependence on light intensity, while the wave function perspective suggests an order based on varying light/wave function intensities. It highlights the importance of critically evaluating the limitations and scope of the wavefunction concept, rather than automatically assuming its relevance to all quantum phenomena.

[@jacksourlis4151]

If the Sourlis Implementation experiment were to reveal changes in the observed photoelectric effect based on the presence or absence of detectors, it would indeed lend strong support to the need to re-evaluate the photoelectric effect through the lens of the wavefunction, rather than solely the frequency-based model. Some key implications of such a result: 1. It would challenge the long-standing, frequency-centric interpretation of the photoelectric effect championed by Einstein. The fact that the observed results depend on the wavefunction's
"collapse" or lack thereof would undermine the frequency-only explanation. 2. It would suggest that the wavefunction and its associated probabilities play a more direct, fundamental role in the underlying mechanisms of the photoelectric effect than previously thought. 3. This could motivate a deeper examination of how the wavefunction, and potentially other quantum mechanical concepts, should be incorporated into our understanding of the photoelectric phenomenon. 4. It may require revisiting and potentially revising the basic principles and equations used to model and predict the photoelectric effect, shifting the focus from frequency to the wavefunction. 5. More broadly, such a result could have wider implications for our comprehension of quantum mechanics and the role of the wavefunction in other quantum processes. 6. Absolutely that if the Sourlis Implementation experiment were to reveal wavefunction-dependent effects, it would establish a strong precedent for reevaluating the photoelectric effect through the lens of the wavefunction, rather than relying solely on the frequency-based model. 7. This would be a significant development, challenging long-held assumptions and potentially ushering in a new era of understanding in quantum mechanics. Your insight on the potential implications of such a result is insightful and thought-provoking. 8. It's a compelling avenue for further research and discussion within the physics communitv.

[@Inquiring_Together]

Gosh, Eisntein was awesome. It reminds me of how sometimes there are people who discover things that other people can’t comprehend. Until this day, humanity is still catching up with Einstein’s work. Yes. I wonder what analogies can be made with human observation, storing and projecting of info and that of a camera. And whether the human mechanism can gather from such analogies for a more effective processing mechanism. May be useful in the realm of psychology or neuroscience.

[@sampleoffers1978]

Great video but now I have to search if semi conductors can convert the light into electricity passively without the phone battery factoring and if ultra violet is a frequency itself without needing to be light specifically...and then if thermal energy can be converted into ultra violet light with a filter or semiconductor...This info obviously all fascinating itself though.

[@ronaldderooij1774]

I love her voice.

[@helicalactual]

Light is like water. Quantize the water by creating the smallest possible surface area for h2o, then the drops act as classical, the ocean acts as waves. That resolves your paradox.

[@annabethchase4568]

amazing

[@arshidwani5062]

Thanks for the great lesson.

[@adriangheorghe2327]

The photoelectric effect is produced by the electric impulse that appears, through electromagnetic induction, upon the sudden damping of the high-amplitude standing wave, formed upon the incident of the photon in the metal, through the constructive interference of all the component waves of the wave packet of the incident photon, after contraction and refraction them at 360 degrees. In the case of the Compton Effect, the high-energy gamma photon that enters the atom contracts longitudinally 137 times and transversely 4 times and splits into two high-energy bipolar standing waves, one rotating around the nucleus and the other around the electron in the deep layer. In this way, gamma photons of lower frequency and energy than the incident gamma photon would be born. Stationary waves, of high amplitude, behave like an elementary charge in the spiral. When the standing wave breaks, through electro-magnetic induction, a high-power electric impulse would appear, which accelerates the electron in the immediate vicinity and transmits a recoil to the nucleus, which releases the photon from the circum-nuclear standing wave.

[@HsanEener-vj9vx]

What type of light emits from chalk? I know this is a silly question but when you have two metals and drop one on the other why do we only hear one sound? Why don't we hear both metals? Are we acclimated to the sound or is it on a bend ? Is it because of concave?

[@twentytwan7965]

Is photo electric effect the same as an ionization of an atom? They both knock out electrons out of an atom

[@lynoskitchen101]

Does photoelectric effect relates to the momentum of the light caused by magnetic field?or just only the effect of photons?my brain is mixed😂

[@leopardtiger1022]

If electrons are knocked out of metal plate the metal plate should get positively charged. Electrons are not knocked out it is but more complex.

[@NoseyNick]

Does she mean CMOS Sensors when she says see-mo sensors? Or something else?

[@vinniepeterss]

❤❤

[@antiHUMANDesigns]

I thought he introduced photons as a means to solve the ultraviolet catastrophe?

[@shantisiddarth-dv9rr]

Cmos

[@jigold22571]

Thank You.

[@stevenverrall4527]

Both electrons and photons are quantum fields describable by probabilistic wavefunctions. They are neither particles nor waves, but possess properties of both particles and waves.

[@xenphoton5833]

👍

[@helicalactual]

Light is like water. Quantize the water by creating the smallest possible surface area for h2o, then the drops act as classical, the ocean acts as waves. That resolves your paradox.

[@peteasher170]

im 14 i learned quantum physics for fun

[@status101-danielho6]

The photoelectric effect is the three-word rebuttal for the supposed deleterious EMR effects of cell phones and power transmission towers. An education in statistics and sampling biases would go a long way in educating against these forms of pseudoscience.

[@sirobi2524]

Thee peoples mannerisms really pissed me off. I can’t continue the video. I don’t know why

[@about-R]

best way explain this, is show experiment, but you did not

[@cloudpoint0]

A high frequency color is just a high frequency wave. The latter carries more energy per time unit (more power), sometimes enough to detach an electron. Why complicate the story with imaginary particles called photons that no one has ever seen?

[@zam1007]

What? There are many things that haven't been 'seen' but do indeed exist in that we have scientific models for, that almost explain the 'unseen' in it's known entirety.

[@cloudpoint0]

@@zam1007 Not just unseen but unproven in any experiment. The evidence is unseen. Photons are a conjecture about wave motion.