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How is superdense coding used in quantum communication?
In quantum information theory, superdense coding (also referred to as dense coding) is a quantum communication protocol to communicate a number of classical bits of information by only transmitting a smaller number of qubits, under the assumption of sender and received pre-sharing an entangled resource.
Who is the third party in superdense coding?
The process starts with a third party, who we’ll call Charlie. Two qubits are prepared by Charlie in an entangled state. He initially starts the 2 qubits in the basis state |0⟩ | 0 ⟩. He applies Hadamard gate ( H H) to the first qubit to create superposition.
What is the channel capacity of superdense coding?
The protocol of superdense coding has been actualized in several experiments using different systems to varying levels of channel capacity and fidelities. In 2004, trapped beryllium 9 ions were used in a maximally entangled state to achieve a channel capacity of 1.16 with a fidelity of 0.85.
Which is the underlying principle of superdense coding?
Superdense coding is the underlying principle of secure quantum secret coding. The necessity of having both qubits to decode the information being sent eliminates the risk of eavesdroppers intercepting messages.
https://www.youtube.com/watch?v=69oelOsr_UY
In other words, we can say it is a protocol that destroys the quantum state of a qubit in one location and recreates it on a qubit at a distant location, with the help of shared entanglement. Superdense coding is a procedure that allows someone to send two classical bits to another party using just a single qubit of communication.
How are two qubits prepared in superdense coding?
Two qubits are prepared by Charlie in an entangled state. He initially starts the 2 qubits in the basis state |0⟩ | 0 ⟩. He applies Hadamard gate ( H H) to the first qubit to create superposition. He then applies CNOT gate ( CX C X) using the first qubit as a control and the second as the target.
How does Bob decode Alice’s message in superdense?
Bob receives Alice’s qubit (rightmost qubit) and uses his qubit to decode Alice’s message. Notice that he does not need to have knowledge of the state in order to decode it — he simply uses the restoration operation. Bob applies a CNOT gate using the rightmost qubit as control and the leftmost as target.