Collapsing a perfect superposition to a chosen quantum state without measurement

Area of Science:

• Quantum Computing
• Quantum Information Science

Background:

• Quantum systems often exist in superpositions of multiple states.
• Collapsing these superpositions to a desired state is crucial for quantum information processing.

Purpose of the Study:

• To propose a novel, fast quantum algorithm for collapsing a perfect superposition to a chosen quantum state.
• To achieve state collapse without employing any measurements.

Main Methods:

• The algorithm utilizes a phase destruction mechanism.
• It involves two operators: one for marking the target state via phase shift and entanglement, and another for selective phase shifts based on Hamming distance.

Main Results:

• A fast quantum algorithm is presented for collapsing a perfect superposition to a target state.
• The method successfully avoids the need for direct quantum measurements.

Conclusions:

• The proposed algorithm provides an efficient way to prepare specific quantum states from a superposition.
• The technique is valuable for testing quantum memories and linear optics quantum computers.
• The number of qubits does not offer a fundamental advantage over measurement-based feedback for this task.