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First Detection and Tunneling Time of a Quantum Walk
Zhenbo Ni1,2, Yujun Zheng1
1School of Physics, Shandong University, Jinan 250100, China.
Entropy (Basel, Switzerland)
|August 26, 2023
Summary
We studied quantum walks with repeated measurements and found that tunneling can speed up particle detection. Introducing a barrier in the quantum walk can lead to earlier detection times.
Area of Science:
- Quantum physics
- Quantum information science
- Condensed matter physics
Background:
- Quantum walks are fundamental models for quantum computation and transport.
- First detection problems analyze the time it takes for a quantum system to be observed.
- Repeated local measurements introduce unique dynamics to quantum walks.
Purpose of the Study:
- To investigate the impact of tunneling on the first detection time in a 1D quantum walk.
- To analyze the effect of a tunneling barrier on the walker's evolution and detection probability.
- To introduce and study the concept of first detection tunneling time.
Main Methods:
- Utilizing the stroboscopic projective measurement protocol.
- Applying the renewal equation to model the detection process.
- Analyzing continuous-time quantum walks on an infinite tight-binding lattice.
Main Results:
- The decay behavior of first detection probability can be controlled by initial conditions.
- A tunneling barrier can lead to earlier detection compared to an impurity-free lattice.
- The evolution of the quantum walker is expedited by tunneling through a barrier under repeated measurements.
Conclusions:
- Tunneling significantly influences the first detection time in quantum walks.
- Quantum walk dynamics can be engineered using barriers to achieve faster detection.
- The first detection tunneling time provides a new metric for studying quantum transport.
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