Entanglement Signals With Distinguishable Non-Orthogonal Coherent Glauber Sender States

Studied Physics at University of California, San Diego Lives in San Francisco, California
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Jack Sarfatti

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NICOLAS GISIN* AND ROB THEW
Group of Applied Physics, University of Geneva, 1211 Geneva 4, Switzerland.
Quantum communication is the art of transferring a quantum state from one place to another. Traditionally, the sender is named Alice and the receiver Bob. The basic motivation is that quantum states code quantum information — called qubits in the case of two-dimensional Hilbert spaces — and that quantum information allows tasks to be performed that could only be achieved far less efficiently, if at all, using classical information. The best known example is quantum key distribution (QKD)1–3. In fact, there is another motivation, at least equally important to most physicists, namely the close connection
between quantum communication and quantum non-locality 4,5, as illustrated by the fascinating process of quantum teleportation 6.
...

The basic procedure is as follows. Alice encodes the state she wants to communicate into a quantum system and sends it to Bob.
Entanglement is exploited to prepare the desired quantum state at a distance. The quantum state is then teleported from Alice to Bob
and the entanglement is also teleported — entanglement swapping ... "The correlations P(a,b|x,y) carry a lot of structure. Apart
from being non-negative and normalized, the local marginals are independent of the

experiment performed by independent observers: ΣaP(a,b|x,y) = P(b|y), is independent

of the experiment x performed by Alice."

It is this last statement that is violated using the distinguishable non-orthogonal
Alice coherent Glauber sender states.
Jack Sarfatti If Alice uses over-complete conjugate Glauber coherent states |z) and |z*) where z = ^1/2exp[i@] and Bob uses a simple 2D qubit with base states |1) & |0) & if we can make the entangled state

‎|z)|1) + |z*)|0) then the signal strength for Bob to see |1) output is

Bob(1) ~ 1 + |(z|z*)|^2

the nonlocal entanglement signal message is encoded in the time dependence (modulation) of (z|z*) =/= 0

Note that if Alice's sender states are orthogonal there is no entanglement signal. Glauber coherent states are distinguishably non-orthogonal and can be modulated in time to encode a message that is locally decodable without a classical signal key as in the quantum teleportation protocol. This casts doubt on the no-entanglement signal arguments. See David Kaiser's June 2012 Scientific American article on Nick Herbert's FLASH.

Entanglement Signals With Distinguishable Non-Orthogonal Coherent Glauber Sender States

Jack Sarfatti