  In the search for quantum advantage with near-term quantum devices,
navigating the optimization landscape is significantly hampered by the barren
plateaus phenomenon. This study presents a strategy to overcome this obstacle
without changing the quantum circuit architecture. We propose incorporating
auxiliary control qubits to shift the circuit from a unitary $2$-design to a
unitary $1$-design, mitigating the prevalence of barren plateaus. We then
remove these auxiliary qubits to return to the original circuit structure while
preserving the unitary $1$-design properties. Our experiment suggests that the
proposed structure effectively mitigates the barren plateaus phenomenon. A
significant experimental finding is that the gradient of $\theta_{1,1}$, the
first parameter in the quantum circuit, displays a broader distribution as the
number of qubits and layers increases. This suggests a higher probability of
obtaining effective gradients. This stability is critical for the efficient
training of quantum circuits, especially for larger and more complex systems.
The results of this study represent a significant advance in the optimization
of quantum circuits and offer a promising avenue for the scalable and practical
implementation of quantum computing technologies. This approach opens up new
opportunities in quantum learning and other applications that require robust
quantum computing power.
