Protectability of IBMQ Qubits by Dynamical Decoupling Technique

We study the current effectiveness of the dynamical decoupling technique on a publicly accessible IBM quantum computer (IBMQ). This technique, also known as bang-bang decoupling or dynamical symmetrization, consists of applying sequences of pulses for protecting a qubit from decoherence by symmetrizing the qubit-environment interactions. Works in the field have studied sequences with different symmetries and carried out tests on IBMQ devices typically considering single-qubit states. We show that the simplest universal sequences can be interesting for preserving two-qubit states on the IBMQ device. For this, we considered a collection of single-qubit and two-qubit states. The results indicate that a simple dynamical decoupling approach using available IBMQ pulses is not enough for protecting a general single-qubit state without further care. Nevertheless, the technique is beneficial for the Bell states. This encouraged us to study logical qubit encodings such as {|0 > L equivalent to 01 >,|1 > L equivalent to|10 >, where a quantum state has the form |psi ab >=a|0 > L+b|1 > L. Thus, we explored the effectiveness of dynamical decoupling with a large set of two-qubit |psi ab > states, where a and b are real amplitudes. With this, we also determined that the |psi ab > states most benefiting from this dynamical decoupling approach and slowed down the decay of their survival probability.

Automated summary

We studied the effectiveness of the dynamical decoupling technique on an IBM quantum computer. The technique protects qubits from decoherence by symmetrizing the qubit-environment interactions. We found that simple universal sequences are effective for preserving two-qubit states on the IBMQ device, but additional care is needed for protecting general single-qubit states.