Patrick Gill | |
|---|---|
 Gill in 2016 | |
| Alma mater | |
| Employer | |
| Awards | |
| Website | www |
| Scientific career | |
| Thesis | Charge Transfer as a Laser Excitation Mechanism (1975) |
| Doctoral advisor | Colin Webb |
Patrick Gill MBE FRS [1] is a Senior NPL Fellow in Time & Frequency at the National Physical Laboratory (NPL) in the UK. [2] [3]
Gill was educated at the University of Sussex and the University of Oxford where he was awarded a Doctor of Philosophy degree in 1975 for research on Charge Transfer as a Laser Excitation Mechanism. [4]
Gill's research is concerned with laser frequency stabilisation techniques for very high resolution spectroscopy, and the development of leading-edge optical atomic clocks that look to form the basis of a future redefinition of the SI base unit second. [5] These include optical clocks based on laser-cooled single ions confined in radiofrequency traps and neutral atoms held in optical lattices, and which now reach uncertainties below that of the caesium fountain primary frequency standard. [1] [6]
Additionally, he has developed a range of stable lasers and optical metrology instrumentation with application to high technology sectors such as precision engineering and manufacture, space science, satellite navigation, Earth observation, defence and security and optical telecommunications. [7] [8] [9] [10]
Gill is a Fellow of the Institute of Physics (FInstP) and was awarded their Young Medal and Prize in 2008 for world-leading contributions to optical frequency metrology. He also received the I. I. Rabi Award in 2007 from the IEEE International Frequency Control Symposium for contributions to time and frequency metrology and the realisation of single ion optical frequency standards. More recently, his group received the Royal Institute of Navigation's Duke of Edinburgh Award in 2014 for long term atomic clock development. [1] Patrick is a visiting professor at Imperial College London and the University of Oxford. He was awarded an MBE for services to Science in The Queen's 2015 New Year Honours. [11] Gill was elected a Fellow of the Royal Society (FRS) in 2016. [1]
The second is the unit of time in the International System of Units (SI), historically defined as 1⁄86400 of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each. "Minute" comes from the Latin pars minuta prima, meaning "first small part", and "second" comes from the pars minuta secunda, "second small part".
The National Physical Laboratory (NPL) is the national measurement standards laboratory of the United Kingdom. It sets and maintains physical standards for British industry.
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A nuclear clock or nuclear optical clock is a notional clock that would use the frequency of a nuclear transition as its reference frequency, in the same manner as an atomic clock uses the frequency of an electronic transition in an atom's shell. Such a clock is expected to be more accurate than the best current atomic clocks by a factor of about 10, with an achievable accuracy approaching the 10−19 level. The only nuclear state suitable for the development of a nuclear clock using existing technology is thorium-229m, a nuclear isomer of thorium-229 and the lowest-energy nuclear isomer known. With an energy of about 8 eV, the corresponding ground-state transition is expected to be in the vacuum ultraviolet wavelength region around 150 nm, which would make it accessible to laser excitation. A comprehensive review can be found in reference.
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An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions between such states they interact with a very specific frequency of electromagnetic radiation. This phenomenon serves as the basis for the International System of Units' (SI) definition of a second:
The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency, , the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s−1.
A quantum clock is a type of atomic clock with laser cooled single ions confined together in an electromagnetic ion trap. Developed in 2010 by physicists at the U.S. National Institute of Standards and Technology, the clock was 37 times more precise than the then-existing international standard. The quantum logic clock is based on an aluminium spectroscopy ion with a logic atom.
In condensed matter physics, a time crystal is a quantum system of particles whose lowest-energy state is one in which the particles are in repetitive motion. The system cannot lose energy to the environment and come to rest because it is already in its quantum ground state. Time crystals were first proposed theoretically by Frank Wilczek in 2012 as a time-based analogue to common crystals – whereas the atoms in crystals are arranged periodically in space, the atoms in a time crystal are arranged periodically in both space and time. Several different groups have demonstrated matter with stable periodic evolution in systems that are periodically driven. In terms of practical use, time crystals may one day be used as quantum computer memory.
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Helen Sarah Margolis is a British physicist who is a Senior Fellow and Head of Science for Time and Frequency at the National Physical Laboratory. Her research considers the use of optical frequency metrology using femtosecond combs.
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