Scrambling and Quantum Teleportation

Abstract

Scrambling is a concept introduced from information loss problem arising in black hole. In this paper we discuss the effect of scrambling from a perspective of pure quantum information theory. We introduce $7$-qubit quantum circuit for a quantum teleportation. It is shown that the teleportation can be perfect if a maximal scrambling unitary is used. From this fact we conjecture that ``the quantity of scrambling is proportional to the fidelity of teleportation''. In order to confirm the conjecture we introduce $\theta$-dependent partially scrambling unitary, which reduces to no scrambling and maximal scrambling at $\theta = 0$ and $\theta = \pi / 2$, respectively. Then, we compute the average fidelity analytically, and numerically by making use of qiskit (version $0.36.2$) and $7$-qibit real quantum computer ibm$\_$oslo. Finally, we conclude that our conjecture can be true or false depending on the choice of qubits for Bell measurement.