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Entangled Photons Maintained Under New York Streets

physics.aps.org

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Re: Entangled Photons Maintained Under New York Streets

#31

Post by Log_out_ »

dhosek wrote: post #11
ars wrote: post #6

Earlier quoted context omitted.

In a public area you can not transport objects, the intention being that the Sabbath is a day of rest, and you should stay home or at least near your home and not do work. Note: Jewish law very carefully defines "public area", and it would take several pages of text to fully explain it, so before objecting be aware you may be lacking background knowledge.

I’m guessing it’s the cubits that gave pause more than the restriction. I first became aware of eruvim thanks to an article in the L.A. Times which talked about a new eruv being constructed in Venice. The article talked about the restriction on carrying and how the eruv allowed congregants to bring their keys¹ with them while attending synagogue. ⸻ 1. Doubtless someone reading this is thinking, well, they could just…

Thus religous law gives birth to a new generation with a hacker mindset.

Re: Entangled Photons Maintained Under New York Streets

#32

Post by lo_zamoyski »

pokepim wrote: post #8
bqmjjx0kac wrote: post #4

Earlier quoted context omitted.

Find a new apartment? Here's the FCC broadband map: https://broadbandmap.fcc.gov/home

Is this solution to every issue in the US? Like if something is shit then instead of fixing just run from the problem? I guess that’s why you are stuck choosing between republicans and democrats every 4 years lol.

The reason Republicans and Democrats win all the time is partly because the US generally doesn't have ranked choice voting when it comes to something like presidential elections [0]. People are afraid of voting for a third party because it is unlikely they would win, so they vote as if betting or hedging, choosing the least bad and yet still likely to win against the worse option. With ranked choice voting, voters could choose their preferred candidate first, and their backup second, and this would introduce some dynamism into the political system.

[0] https://en.wikipedia.org/wiki/Ranked-choice_voting_in_the_Un...

EDIT: Rated voting seems even better [1]

[1] https://en.wikipedia.org/wiki/Rated_voting

Re: Entangled Photons Maintained Under New York Streets

#33

Post by nightowl_games »

LgWoodenBadger wrote: post #16

How does one detect whether a pair is still entangled?

I'm under the impression you can't. You create an environment that is more likely to keep the sets of particles from interacting with anything else and then you create an entangled pair. To confirm the entanglement I believe would take several measurements of several pairs of particles and these measurements would result in a probability that they were still entangled, not a certainty.

I found this explanation:

https://www.quora.com/Is-it-possible-to-detect-if-a-particle...

In my opinion, it's not the entanglement that is interesting or confusing, it's the super positions of both particles before they are measured that is hard to explain... How can two particles be in super positions of two states but then when you measure them they are always complimentary? Either it was "spooky action at a distance" ie (particle A communicated it's measurement result to particle B) or there is "hidden variables" inside the super positions that determines the result of the measurements.

Re: Entangled Photons Maintained Under New York Streets

#34

Post by rockskon »

Maxatar wrote: post #27
rockskon wrote: post #10

Earlier quoted context omitted.

Doesn't that map consider an entire region serviced if a single residence in that entire region can get the advertised speeds?

That is technically true but usually companies don't invest the kind of resources to support fiber just to service a handful of residences. Once the infrastructure is in place, you usually try to deploy it to as many homes as possible.

If further expansion is seen as unlikely to recoup costs then what's to say an entire neighborhood has service when fiber has only been run to a single apartment?

I've seen complaints amounting to this exact scenario for years.

Re: Entangled Photons Maintained Under New York Streets

#36

Post by fmj »

rockskon wrote: post #34
Maxatar wrote: post #27

Earlier quoted context omitted.

That is technically true but usually companies don't invest the kind of resources to support fiber just to service a handful of residences. Once the infrastructure is in place, you usually try to deploy it to as many homes as possible.

If further expansion is seen as unlikely to recoup costs then what's to say an entire neighborhood has service when fiber has only been run to a single apartment? I've seen complaints amounting to this exact scenario for years.

My friend has the opposite problem. The ISP's map claims to offer fiber service on his whole block, and if you type in your address they'll even offer service at that specific address. The problem is his block is at least 80% multi-tenant dwellings, and they'll only do new installs if everyone in the building subscribes. They don't just want permission from the landlord to wire the whole building at once to save time if future tenants subscribe, they're just not gonna do it unless everyone pays. In my friend's case, they didn't even tell him this ahead of time, despite explicitly saying he was in an apartment on the form he filled out when he attempted to sign up. They just "helpfully" change it to a request for DSL service. This was explained to my friend by the technician that showed up with DSL hardware only capable of a faction of the speed he was currently getting on coax. Obviously, he refused service. Then he got to fight AT&T for a few months over bills for DSL services he never requested, and rental for hardware he never accepted.

Re: Entangled Photons Maintained Under New York Streets

#38

Post by renox »

rdtsc wrote: post #29
LgWoodenBadger wrote: post #16

How does one detect whether a pair is still entangled?

Easy-peasy. They will periodically see if the photons, when measured had already been measured by an eavesdropper. In quantum world measurement will affect the entangled system, so it’s impossible for someone to measure (read) the data in between without it being detected at both ends.

> so it’s impossible for someone to measure (read) the data in between without it being detected at both ends.

You give too little information for this to be understandable.

Re: Entangled Photons Maintained Under New York Streets

#40

Post by rdtsc »

renox wrote: post #38
rdtsc wrote: post #29

Earlier quoted context omitted.

Easy-peasy. They will periodically see if the photons, when measured had already been measured by an eavesdropper. In quantum world measurement will affect the entangled system, so it’s impossible for someone to measure (read) the data in between without it being detected at both ends.

> so it’s impossible for someone to measure (read) the data in between without it being detected at both ends. You give too little information for this to be understandable.

That's one of the fundamentals of quantum mechanics. How that works on the intuitive level, is still being debated. All the mathematics and the experimental results support that with an extremely high level confidence though.

Not sure if a HN comment is a right to go back to the fundamentals here either, but I'll try again: reading the quantum information means to "measure it". Measurement alters the state of the system. If someone then "measures" it (i.e. "reads", i.e "eavesdrops"), the communicating parties will find out.

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