Quantum-Limited and Ultra-Precision Measurements

Jincheng Zhang

This paper explores the potential of utilizing quantum entanglement for achieving ultra-high precision measurements through a distributed system. The core claim centers on leveraging entangled quantum bits to surpass the limitations imposed by conventional measurement techniques. The proposed mechanism involves constructing a network of entangled quantum bits, enabling the collection and analysis of data with unprecedented accuracy. This approach addresses a fundamental bottleneck in precision measurement, offering new avenues for scientific research and technological advancements. The theoretical framework presented outlines the principles and potential benefits of this entanglement-based distributed measurement system. ---

Art Hobson

John C. Gallop

SQUIDs are used extensively across the world of precision measurement in physics and many other sciences, including earth science studies and medicine, providing some of the most precise measurements possible. The paper will discuss some of the limits to SQUID measurements which emerge in these various fields. One of the newer areas of interest is the use of SQUIDs to measure the properties of nanomagnetic particles or even single spins. This is driven by the needs of future ultra high density magnetic storage and quantum information processing. The paper will focus on this issue and will propose some hard limits as well as some means by which the present state-of-the-art may be extended towards those limits.

Asghar Ullah, Vipul Upadhyay, Özgür Esat Müstecaplıoğlu

We propose a scheme to enhance the range and precision of ultra-low temperature measurements by employing a probe qubit coupled to a chain of ancilla qubits. Specifically, we analyze a qubit chain governed by Heisenberg XX and Dzyaloshinskii-Moriya (DM) interactions. The precision limits of temperature measurements are characterized by evaluating quantum Fisher information (QFI). Our findings demonstrate that the achievable precision bounds, as well as the number of peaks in the QFI as a function of temperature, can be controlled by adjusting the number of ancilla qubits and the system's model parameters. These results are interpreted in terms of the influence of energy transitions on the range and the number of QFI peaks as a function of temperature. This study highlights the potential of the probe qubit-ancilla chain system as a powerful and precise tool for quantum thermometry in the ultra-low temperature regime.

Pierre Meystre