State Transfer and Spin Measurement

Abstract

We present a Hamiltonian that can be used for amplifying the signal from a quantum state, enabling the measurement of a macroscopic observable to determine the state of a single spin. We prove a general mapping between this Hamiltonian and an exchange Hamiltonian for arbitrary coupling strengths and local magnetic fields. This facilitates the use of existing schemes for perfect state transfer to give perfect amplification. We further prove a link between the evolution of this fixed Hamiltonian and classical Cellular Automata, thereby unifying previous approaches to this amplification task. Finally, we show how to use the new Hamiltonian for perfect state transfer in the, to date, unique scenario where total spin is not conserved during the evolution, and demonstrate that this yields a significantly different response in the presence of decoherence.

4 pages, 2 figures

References in corpus (10)

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Cited by in corpus (15)

• Quantum Communication through Spin Chain Dynamics: an Introductory Overview
• Simulations of Information Transport in Spin Chains
• Dynamics and Control of a Quasi-1D Spin System
• Quantum Ratchets for Quantum Communication with Optical Superlattices
• Quantum state transfer and time-dependent disorder in Quantum Chains
• Effective one-body dynamics in multiple-quantum NMR experiments
• Adiabatic Quantum Transport in a Spin Chain with a Moving Potential
• Iterative quantum state transfer along a chain of nuclear spin qubits
• Control-limited perfect state transfer, quantum stochastic resonance and many-body entangling gate in imperfect qubit registers
• The Non-Equilibrium Reliability of Quantum Memories
• Interfacing with Hamiltonian Dynamics
• Heisenberg chains cannot mirror a state
• Quantum State Transfer with Spin Chains
• Graph state generation with noisy mirror-inverting spin chains
• NMR method for amplification of single spin state