New answers tagged

0

From a classical standpoint, it seems pretty clear that information can be easily lost. Nope, classical mechanics is reversible. It's so reversible that you can't even squeeze the state space: states that start out "very different" stay "very different". Those vague terms are formalized by Liouville's theorem. Because classical mechanics is reversible, ...


-1

Yes. I believe it is done from Lagrange multipliers. This whole maximum entropy is in most textbooks on statistical mechanics. The configurational entropy of a system will tend to increase... Or have i misunderstood your question?


1

Your definition of Holevo information is wrong. It corresponds to $C_{ea} $, the entanglement assisted capacity of the channel. See equation (5) of the paper. The Holevo information is defined for a probabilistic mixture of density matrices, or for a cq-state (cq = classical quantum state).


3

Quantum teleportation works on any qubit. It isn't restricted to only working on entangled qubits. It works on unentangled qubits. Quantum teleportation does require the sender and receiver to have shared an EPR pair $P_{A,B}$ in order to send your qubit $|\psi\rangle$, and the teleportation process will use up $P_{A,B}$, but there is no restriction on ...


3

Take a pair of qubits in a maximally entangled state $\phi=A\otimes B+B\otimes A$. (Here $A$ and $B$ are a basis for the state space of a single qubit.) One stays with you, the other resides at the intended location. You've therefore got two qubits --- the one you want to transport (in state $\psi$) and one of the entangled pair. Now make an observation ...


0

The book in question is self-published, and a cursory glance through it and some of the author's other writings convinces me that he is almost certainly a crackpot (although perhaps self-educated enough to sound convincing to one who might not know better). If you have a true interest in topics about space and particle physics (and, if so, good for you!), I ...


1

You are right. You can only (repeatedly) simulate a system where you have perfect knowledge of the quantum state. If you don't have perfect knowledge of the quantum state, a "perfect" simulation in the sense you have in mind is not possible. If the system is very small, you can try to projectively measure all quantum states. Then you have destroyed all ...



Top 50 recent answers are included