informational diode

[swansont]

2 hours ago, MJ kihara said:

Radio device involves sending photons while entanglement communication device involves utilization of entanglement to communicate... which signal arrive first?

Repeating this does not clarify what the “entanglement communication device” is. It’s not a category of equipment (as opposed to, say a radio, or a laser, which are common technologies) Does it send photons? If so, the signals arrive at the same time. Does it send one of a particle pair, like electrons? Then it will take longer.

As Mordred points out, entanglement is used for encryption. “entanglement communication device” doesn’t describe the communication part.

19 hours ago, hoola said:

I am proposing entangling the two balls in proximity, then moving ball 2 beyond ball one's light cone before measuring ball one.

How can you do this, seeing as the light cone expands at c, and the ball travels slower?

[MJ kihara]

9 hours ago, swansont said:

“entanglement communication device”

A device capable of detecting wave function of an entangled state...when quantum particle A is entangled to quantum particle B then these particles are separated held into different device,one device is carried by space ship and another left behind on Earth ...the one left behind holding particle B let's say initiates a reaction when it detects change of state of particle B of course caused by wave function collapse...once the crew reaches proxima centauri they take their device holding particle A interfere with it, the device left on Earth detect change of state of B then initiates a reaction,that way a signal has been sent...which happens instantly. 

[swansont]

4 hours ago, MJ kihara said:

A device capable of detecting wave function of an entangled state...when quantum particle A is entangled to quantum particle B then these particles are separated held into different device,one device is carried by space ship and another left behind on Earth ...the one left behind holding particle B let's say initiates a reaction when it detects change of state of particle B of course caused by wave function collapse...once the crew reaches proxima centauri they take their device holding particle A interfere with it, the device left on Earth detect change of state of B then initiates a reaction,that way a signal has been sent...which happens instantly. 

The device you describe is fiction.

Entanglement does not detect a change of state of a particle. The particle is in an undetermined state. When it’s measured, you can then send that information to the other detector to compare. That signal is limited to traveling at c.

 

[MJ kihara]

3 hours ago, swansont said:

Entanglement does not detect a change of state of a particle. The particle is in an undetermined state. When it’s measured, you can then send that information to the other detector to compare. That signal is limited to traveling at c.

 

The device is the one detecting change of state.... entanglement in this case induces wave function synchronization of particle A and B.

When measurements are done to particle A it's wave function collapse forcing particle B to change state,then the device back on Earth detects this change of state... Whichever the state of particle A and B are initially does not matter, in this case,what matter is any change of state induced by measurements affects the entangled system (A and B) no matter how part they are as long as they are entangled...no need to compare...what is needed is a signal no matter how trivial it is.

The device is fictional because of our current civilization technological know how.

[swansont]

8 minutes ago, MJ kihara said:

The device is the one detecting change of state.... entanglement in this case induces wave function synchronization of particle A and B.

When measurements are done to particle A it's wave function collapse forcing particle B to change state,then the device back on Earth detects this change of state... Whichever the state of particle A and B are initially does not matter, in this case,what matter is any change of state induced by measurements affects the entangled system (A and B) no matter how part they are as long as they are entangled...no need to compare...what is needed is a signal no matter how trivial it is.

The device is fictional because of our current civilization technological know how.

It’s fictional because that’s not how entanglement works. B isn’t in an eigenstate, it’s in a superposition, so there is no change from one eigenstate to another, and since it wasn’t in an eigenstate, measuring the state doesn’t transmit any signal. You have to tell the other end  via normal communication.

[MJ kihara]

47 minutes ago, swansont said:

It’s fictional because that’s not how entanglement works. B isn’t in an eigenstate, it’s in a superposition, so there is no change from one eigenstate to another, and since it wasn’t in an eigenstate, measuring the state doesn’t transmit any signal.

Let's say AB were an entangled pair of electrons,A with spin up and B with spin down .....your taking them apart,your measurements flips spin of A... what will happen to the spin of B?

Why does for entanglement to occur,it require close proximity interaction?

57 minutes ago, swansont said:

You have to tell the other end  via normal communication.

This sound like a conspiracy...is it a must?

[swansont]

10 minutes ago, MJ kihara said:

Let's say AB were an entangled pair of electrons,A with spin up and B with spin down .....your taking them apart,your measurements flips spin of A... what will happen to the spin of B?

If you know A has spin up, or B has spin down, then the particles are not entangled. 

Entanglement could only occur if you don’t know the individual spins, but know the total spin of the pair (zero, in this case)

10 minutes ago, MJ kihara said:

Why does for entanglement to occur,it require close proximity interaction?

Interaction strength tends to drop off with distance.

10 minutes ago, MJ kihara said:

This sound like a conspiracy...is it a must?

It’s how it works.

[MJ kihara]

57 minutes ago, swansont said:

If you know A has spin up, or B has spin down, then the particles are not entangled. 

Knowing the spin of A and B and bringing A and B into close proximity which one takes precedence for entanglement to occur?

[swansont]

3 minutes ago, MJ kihara said:

Knowing the spin of A and B and bringing A and B into close proximity which one takes precedence for entanglement to occur?

You would have to have an interaction where you no longer knew the individual spins for them to be entangled.

[MJ kihara]

16 minutes ago, swansont said:

You would have to have an interaction where you no longer knew the individual spins for them to be entangled.

Meaning that you can have an interaction of quantum particles(electron),but as long as you know the individual spin of the electron(A&B) prior to interaction entanglement of their spin won't take place? Iow interaction of quantum particle in close proximity without entanglement is possible.

[swansont]

3 minutes ago, MJ kihara said:

Meaning that you can have an interaction of quantum particles(electron),but as long as you know the individual spin of the electron(A&B) prior to interaction entanglement of their spin won't take place?

If you know their spins, they aren’t entangled.

3 minutes ago, MJ kihara said:

Iow interaction of quantum particle in close proximity without entanglement is possible.

Yes, interaction without entanglement is possible.

[hoola]

it seems that if entanglement phenomena are ever to be used for communications, one would have to determine the state of the proximate photon just before, or as it is measured.  If you could make a parameter determination past the traditionally  established  probability state, by using error correction, it seems communication of a  bit by bit mode could be established, so many entangled particles would be needed, depending on the length of the communication text.

[Genady]

19 minutes ago, hoola said:

it seems that if entanglement phenomena are ever to be used for communications, one would have to determine the state of the proximate photon just before, or as it is measured.  If you could make a parameter determination past the traditionally  established  probability state, by using error correction, it seems communication of a  bit by bit mode could be established, so many entangled particles would be needed, depending on the length of the communication text.

This is not possible according to this theorem:

Quote

In physics, the no-communication theorem or no-signaling principle is a no-go theorem from quantum information theory which states that, during measurement of an entangled quantum state, it is not possible for one observer, by making a measurement of a subsystem of the total state, to communicate information to another observer.

No-communication theorem - Wikipedia

[Mordred]

Not if you send numerous entangled photons. When Alice examines her photon stream Bob also examines his. If the  photons are not opposite to one another on every pair then you would know you had corruption or a security breach

Here is some of the encryption methods that have been suggested.

https://arxiv.org/pdf/2003.07907

The easiest example the paper gives is through parametric down conversion. You will know the initial frequencies but once the beam passes through the beam splitter you wouldn't know which polarity is sent until you examine. From this you can apply the conservation laws and expect the opposite polarity at end.

 If you font have the opposite polarity at each end then you know something occurred to interfere with the signal.

Edited June 9, 2023 by Mordred

[hoola]

 if you have to have many entangled pairs in both places, held as an inventory, using each measured pair as one bit of information. Of course, since a state cannot be determined, the concept is unworkable unless "weak measurement" has some application

[Mordred]

Think of it this way the applications in that paper don't describe encrypted messages. They describe means of detecting security breaches. It's something on the order of error detection  methods used by computers today. Older examples being checksum or Cyclic redundancy checks.

[StringJunky]

On 6/8/2023 at 12:50 PM, Mordred said:

Typically entanglement will involve a particle to particle interaction  the most common method is particle pair creation such as through parametric down conversion using a beam splitter for photons.

The probability correlation function can then be determined by applying the various conservation laws such as conservation of charge, energy momentum, lepton number, isospin, color, flavor etc.

Entanglement can be used in communication for cryptology. However no communication exceeds c

 

Is quantum cryptology where the entanglement is used as a trigger to notify of a breach; an attacker collapses the wavefunction?

e2a I'll make it a question

Edited June 10, 2023 by StringJunky

[Mordred]

In essence yes that a succinct way to describe it.

[StringJunky]

16 minutes ago, Mordred said:

In essence yes that a succinct way to describe it.

That is clever stuff. It's new to me. 

Edited June 10, 2023 by StringJunky

[Mordred]

 There is getting to be a decent number of papers on the application. I've been running across them quite often. I haven't heard of any tests done yet. Largely still in the proposal stages.

[StringJunky]

43 minutes ago, Mordred said:

 There is getting to be a decent number of papers on the application. I've been running across them quite often. I haven't heard of any tests done yet. Largely still in the proposal stages.

Yeah, I was going to ask how long to filter down to consumers... LOL!

[Mordred]

Lol not quite there yet 

[MJ kihara]

10 hours ago, swansont said:

Yes, interaction without entanglement is possible.

On the issue of knowing and issue of interaction on close proximity....to know you have to make measurements.... making measurements means coming into closer proximity to the quantum particle being measured for accuracy of your measurements to improve,closer to the extent uncertainties takes over...when the signal from test particle come back to you so that you know,entanglement is destroyed..if the signal you used for measurements doesn't come back and stick to the quantum particle being measured then entanglement is not destroyed.

I think for quantum particle or quantum particles,any kind of interaction at closing proximity,it involves entanglement.....by knowing the state of entanglement you are destroying the existing interaction of the system and the system is no longer in the entangled form that you knew...iow i think AT CLOSE PROXIMITY for quantum particle/s you can't separate interaction and entanglement (interaction without entanglement is impossible).....detection/knowing, you are destroying the interaction since you have to get something out of the interaction to be the signal your getting to make you know.

 

 

 

[swansont]

4 hours ago, MJ kihara said:

I think for quantum particle or quantum particles,any kind of interaction at closing proximity,it involves entanglement

A photon causing an excitation of an atom is destroyed - it no longer exists - so it can’t be entangled.

[MJ kihara]

1 hour ago, swansont said:

A photon causing an excitation of an atom is destroyed - it no longer exists - so it can’t be entangled.

Perhaps entanglement happens prior to the 'destruction' of the photon and prior to emission of the photon when the atom undergoes relaxation.......''anyway from my thinking,'the other concept' a photon causing excitation is not destroyed,and it still exists in photon zone within the electron,whereby it's then emitted when the election is deexicited.... sorry for being off conventional"