If you have ever been without your best friend, you may both find yourselves behaving similarly, almost as if you were together. By definition, you and your friend are entangled ― having a relationship based on probability (NASA, 2016). With particles, quantum entanglement is slightly more complicated.
Quantum entanglement is a phenomenon where the states of two particles cannot be determined independently, no matter how far apart they are. Entangled particles behave as if they are together, acting as a single system, even though they are completely separated in space. Experiments showcasing quantum entanglement have included electrons, photons, and neutrinos, in some molecules the size of small diamonds and in some, as large as buckyballs. If you took two entangled particles and measured the spin of one of those particles, you could be certain that the other particle would have the opposite spin (NASA, 2016). You would not have to measure the second particle, as information from the first particle is communicated to the second. This occurs by the principle of nonlocality, which is the idea that these particles are not being directly affected by their surroundings, but by each other, at a distance. Einstein famously called this “spooky action at a distance” (Boughn, 2016). This concept prompted many questions from scientists and the public alike. Though it has been on scientists’ minds for years, we are only now seeing physical evidence of its existence (Figure 1), thanks to scientists at the University of Glasgow.
So, why does nonlocality matter? When we give directions, we often relate the location of the destination to landmarks around it. Everything is “here” relative to everything else. Your computer is on the table, which is on the floor. But, where exactly is your computer? Where exactly is the floor? You could assign coordinates to these entities, but if you came back to those coordinates a year from now, or a decade from now, would you be in exactly the same position as you were? Likely not. Tectonic plates shift, gravitational ripples occur, and spacetime is redefined (Musser, 2015). Spacetime does not support localized structures; it must support systems ― holistic entities ― that can change with energy, which cannot be positioned at a specific place (Musser, 2015). Entangled particles operate much the same. They are a system, working together, non-locally. They do not have defined positions, but they do have defined distance.
As we discover more about entanglement and nonlocality, we discover more questions. What is “here”? What is time? How can one particle be in two different places, acting at the exact same time? One thing is for certain; if you ever want to know what your friend is doing, you need not ask. They are probably wondering the same thing.
References
Boughn, S., 2016. Making sense of Bell’s theorem and quantum nonlocality. Arxiv, [e-journal], https://doi.org/10.1007/s10701-017-0083-6
Landau, E., 2016. Particles in love: quantum mechanics explored in new study. NASA, [online] Available at: https://www.nasa.gov/feature/jpl/particles-in-love-quantum-mechanics-explored-in-new-study [Accessed 2 October 2019].
Musser, G., 2015. How Einstein revealed the Universe’s strange “nonlocality”. Scientific American, [online] Available at: https://www.scientificamerican.com/article/how-einstein-revealed-the-universe-s-strange-nonlocality/ [Accessed 1 October 2019].
Image
University of Glasgow, 2019. Scientists unveil image of quantum entanglement. [image online] Available at: https://www.gla.ac.uk/news/headline_655958_en.html [Accessed 1 October 2019].
Comments
5 Responses to “Where is “here”? And other questions not answered by entanglement”
Hello!
I chose to write about quantum entanglement after hearing about it in physics on the first day of school. It sounded so interesting that I had to research more. That research brought me here, to the post you just read. I hope you enjoyed it, or understood something new! I look forward to hearing your feedback.
Have a lovely day,
Aoife
Hi Aoife!
Great blog post! It was so cool to read about quantum entanglement and how it works. I have a few suggestion on things that could be fixed.
Firstly, the reference for the image can just be the author and the year. For example, for your image it could just be “(University of Glasgow, 2019). ”
Secondly, I think it would be scientists’ rather than “scientists’s” in your third paragraph.
Lastly, although you explained the concept of quantum entanglement it would be nice to have a clear definition stated somewhere at the end of the first paragraph or at the beginning of the second paragraph.
Hope that helps!
-Selvi
Hi Selvi,
Thank you so much for your helpful feedback. I will incorporate these suggestions in my final edit. I look forward to producing higher quality work!
Thank you,
Aoife
Hi Aoife
I enjoyed reading your blog post about entanglement! I can’t wait to hear about the impacts of current and future research of quantum entanglement on our current understanding of physics. In general, your blog post had a nice flow and you did a good job of explaining the subject.
Some minor suggestions:
1. In the first paragraph, I found the sentence “Experiments showcasing quantum entanglement have included electrons, photons, and neutrinos, with some molecules as small as diamonds or as large as buckyballs” to be a little unclear (this is probably a personal preference). I would suggest changing ‘with some molecules’ to ‘in some molecules’. You could also say “Experiments with some molecules as small as diamonds or as large as buckyballs have exhibited quantum entanglement in electrons, photons, and neutrinos”.
2. At the end of the first paragraph, I might change “This concept was followed by many questions from scientists and the public alike” to “This concept prompted/inspired/led to many questions from scientists and the public alike”.
3. In the last paragraph before the conclusion, I suggest adding a sentence at the end that links why nonlocality doesn’t matter back to why particles are affected by each other at a distance.
Happy editing,
Shannon
Hey Aoife,
Great blog post! I found the concept very interesting as I remember it being talked about during class, and sparking my interest. It is an amazing phenomenon that no matter how much I research or read about, always brings up more questions than it answers. I had I few suggestions that I found while readings your blog;
1. I would suggest moving the picture down until it is referenced in the text. While I was reading the post, I didn’t realize what I was looking at until I read farther down when you referenced it and found myself scrolling back to find the image.
2. Secondly, I would suggest potentially citing some of the sentences found in the second paragraph when you further explain what entanglement is. For example you state,
“Experiments showcasing quantum entanglement have included electrons, photons, and neutrinos, with some molecules as small as diamonds or as large as buckyballs. If you took two entangled particles and measured the spin of one of those particles, you could be certain that the other particle would have the opposite spin. You would not have to measure the second particle, as information from the first particle is communicated to the second. This occurs by the principle of nonlocality, which is the idea that these particles are not being directly affected by their surroundings, but by each other, at a distance.”
However, none of these ideas are cited. Some of these may be your own ideas, however, some of them sound like things we discussed in class or concepts that would not typically be considered “common knowledge”. I would suggest finding credible sources to site them if possible.
Overall, I enjoyed reading your blog post and wanted to acknowledge how easy it was to follow as far as grammar goes. Great job Aoife, I look forward to reading your final post!
Thanks,
Madie 🙂