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QUANTUM VACUUM METROLOGY

Published on 3/7/2019

LEADING THE WAY IN INNOVATION: NIST'S QUANTUM VACUUM METROLOGY

Significant advances are being made in redefining many of the fundamental physical constants in terms of quantum mechanics. Vacuum plays such a fundamental and all pervasive part in these definitions, not only in terms of the measurement of vacuum but due to the idea that a vacuum must have been present Pre-Big Bang. What vacuum really is, and how we define it, will challenge many of the glaringly problematic definitions of such quantities as dark energy and the cosmological constant, the later for example is smaller by 120 orders of magnitude compared to prediction! One of the huge challenges of modern physics is to work out why.

New instrumentation potentially gives a new view on such problems, challenging the very fabric of our current concepts that make up physics itself.

Innovation and scientific advancement go hand-in-hand. The new quantum-based vacuum devices that NIST for example are developing such as the Photonic Pressure Sensor (see video below) will, we believe, not only lead to new ways we view Nature at a fundamental level, but will lead to completely new useful devices not thought even possible only a few years ago.

The eventual commercial realisation of the higher accuracy FLOC Sensor will allow for the replacement of traditional mercury manometers and therefore will remove much of the toxic mercury from the laboratory and environment.

Recommended reference: "Quantum-based vacuum metrology at NIST", J. Scherschligt, J.A. Fedchak, Z. Ahmed, D.S. Barker, K. Douglass, S. Eckel, E. Hanson, J. Hendricks, N. Klimov, T. Purdy, J. Ricker, R. Singh, J. Stone,
17 May 2018, arXiv:1805.06928, https://arxiv.org/pdf/1805.06928

An extract from the article:
Pressure metrology is particularly challenging in the vacuum, and especially in high vacuum (<10^-4 Pa) where the mean-free-path of molecules are longer than the dimensions of typical laboratory apparatus. Moreover, in the ultra-high vacuum (UHV, <10^-6 Pa)—a pressure regime critical to advanced research and technology there has not existed an absolute pressure sensor. Recently, NIST has launched two initiatives to realize the pascal for vacuum pressures in a fundamentally modern way, by interrogations of quantum mechanical systems that directly relate to the particle density and therefore pressure in the vacuum. The Fixed-Length Optical Cavity(FLOC) is an index of refraction-based measurement. The Cold Atom Vacuum Standard (CAVS) uses cold trapped atoms to sense vacuum. These efforts are consistent with the nascent Quantum-SI which is an emerging effort in the international community to recast the SI (International System of units) in terms of observable quantum phenomena and fundamental constants of nature.

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