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A staple of sci-fi has been a pair of boxes with quantum entangled particles inside allowing FTL communications once the boxes travel (sub-FTL) to their destination. By my understanding that's impossible, although I always wondered if you could coordinate FTL, by detecting when a particle was no longer entangled. Can someone with the background comment?
The interesting part of "quantum communications" is the impact on security and surveillance. Does "quantum communications" even needs switches and routers? Backdoors don't seem to be possible...
As a child I dreamt of having two futuristic walkie-talkies sharing several pairs of entangled particles making perfect instant communication across the galaxy possible. Later my physics teacher crushed my dreams by telling me it's far from as easy as that and probably impossible due to Heisenberg's ... (no clue what it's called in English). It's pretty awesome to hear that something similar is actively being worked…
As a child I dreamt of having two futuristic walkie-talkies sharing several pairs of entangled particles making perfect instant communication across the galaxy possible. Later my physics teacher crushed my dreams by telling me it's far from as easy as that and probably impossible due to Heisenberg's ... (no clue what it's called in English). It's pretty awesome to hear that something similar is actively being worked…
Imagine being able to explore distant planets with robots and VR googles in real time !
A staple of sci-fi has been a pair of boxes with quantum entangled particles inside allowing FTL communications once the boxes travel (sub-FTL) to their destination. By my understanding that's impossible, although I always wondered if you could coordinate FTL, by detecting when a particle was no longer entangled. Can someone with the background comment?
I've always found it easier to explain quantum entanglement thusly:
Imagine you have 2 cubes that alternate glowing between purple and orange. And they stay in one color for a random amount of time (100s of milliseconds). Holding both in your hands, you would just have randomly color-shifting cubes. But a neat trick of these cubes is that when you close your eyes, hit them together, and quickly put them into separate closed boxes, you know that three things will happen:
1. they will be locked into one color as long as the box stays closed (no more alternating)
2. each cube will be the opposite color from each other (when one is purple, the other is orange, and vice versa)
3. when you open the box and observe the cube, it will stay in the current color for 1 second, and then resume its randomness once again.
So you take one of the boxes containing a cube and ship it to your friend on the Moon (greater than 1 light-second away). When she gets the box, you call her on your phone and ask her to wait. Then you open your box and see that your cube is purple. And then the cube starts blinking again because the entanglement is broken on your end. So you wait a few seconds and say to her "open your box and I bet you the cube is orange". She does so and confirms the cube was glowing orange before resuming the random blinking. Now the entanglement is broken on her end, but you "knew" that by having the purple cube in your possession that hers would be orange.
Using this system, there is no way to exploit your knowledge of what the colors will be once observed (so sorry, no FTL communication here). The particles no longer influence each other after they are entangled at the start. It's not an active process, but rather a very specific type of setup. But it still bothers physicists (most famously Einstein), that you could "know" something without direct proof.
And people in general hope that this un-intuitive phenomenon will open up whole new worlds of sci-fi tech. But no, as the article explained: "Nothing we knew suggested this goal was unachievable. The significance of this news is not that it was unexpected or that it overturns anything previously believed, but simply that it’s a satisfying culmination of years of hard work."
If you had shipped the other cube-box to the opposite side of the galaxy, thousands of years after you were long dead, someone would open it and still find an orange cube.
As a child I dreamt of having two futuristic walkie-talkies sharing several pairs of entangled particles making perfect instant communication across the galaxy possible. Later my physics teacher crushed my dreams by telling me it's far from as easy as that and probably impossible due to Heisenberg's ... (no clue what it's called in English). It's pretty awesome to hear that something similar is actively being worked…
A staple of sci-fi has been a pair of boxes with quantum entangled particles inside allowing FTL communications once the boxes travel (sub-FTL) to their destination. By my understanding that's impossible, although I always wondered if you could coordinate FTL, by detecting when a particle was no longer entangled. Can someone with the background comment?
Caveat: I only have a B.Science degree in Engineering Physics (Colorado, USA) and hobbyist-type research in PhD-level physics. I've always found it easier to explain quantum entanglement thusly: Imagine you have 2 cubes that alternate glowing between purple and orange. And they stay in one color for a random amount of time (100s of milliseconds). Holding both in your hands, you would just have randomly color-shifting…
A staple of sci-fi has been a pair of boxes with quantum entangled particles inside allowing FTL communications once the boxes travel (sub-FTL) to their destination. By my understanding that's impossible, although I always wondered if you could coordinate FTL, by detecting when a particle was no longer entangled. Can someone with the background comment?
Caveat: I only have a B.Science degree in Engineering Physics (Colorado, USA) and hobbyist-type research in PhD-level physics. I've always found it easier to explain quantum entanglement thusly: Imagine you have 2 cubes that alternate glowing between purple and orange. And they stay in one color for a random amount of time (100s of milliseconds). Holding both in your hands, you would just have randomly color-shifting…
In reality, you're not measuring colors of boxes, but spins of particles. You generate two particles with opposite spins along a known axis. If you measure the spins along that same axis, you always get the same result: one is spinning "clockwise", the other "counterclockwise".
On the other hand, if you measure one of the spins along a different axis, you'll randomly get "clockwise" or "counterclockwise" according to the angle between the original spin axis and the measurement axis. Measuring at a right angle to the original axis gives you random results, which is also what you'd expect. But what about the angles in between? Classical statistics says the correlation should vary linearly with the angle, but the actual results have a cosine factor (https://en.wikipedia.org/wiki/File:Bell.svg). This cosine factor can't be explained by any kind of classical statistical randomness. That's the "spooky" part.
