Counting Down to the New Ampere (2016)
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Re: Counting Down to the New Ampere (2016)
#2So does this mean that quantum computing will become more viable? Since in quantum computing, calculations are accomplished by measuring the spin of an electron, I would imagine this would increase the throughput to a measurement instrument since this is allowing one electron to pass at a faster pace. While electron measurement instruments still need to be advanced significantly, I would imagine an innovation like this would further advance the reality of true quantum computing. Is this an accurate assessment?
Re: Counting Down to the New Ampere (2016)
#3So does this mean that quantum computing will become more viable? Since in quantum computing, calculations are accomplished by measuring the spin of an electron, I would imagine this would increase the throughput to a measurement instrument since this is allowing one electron to pass at a faster pace. While electron measurement instruments still need to be advanced significantly, I would imagine an innovation like th…
I think you'd also need to redefine the meter and second to speed up light. Unfortunately, the footnote specifies that we can expect only "major changes in the kilogram, ampere, kelvin, and mole" in the new SI 2018, so it seems we'll have to wait for the release after that.
On the bright side, the changes to the kilogram might begin to address the obesity crisis.
Re: Counting Down to the New Ampere (2016)
#4So does this mean that quantum computing will become more viable? Since in quantum computing, calculations are accomplished by measuring the spin of an electron, I would imagine this would increase the throughput to a measurement instrument since this is allowing one electron to pass at a faster pace. While electron measurement instruments still need to be advanced significantly, I would imagine an innovation like th…
> So does this mean that quantum computing will become more viable?
Not really. Detecting the voltage or current differences that you need for detecting an electron spin, that's a very different thing than doing the quantitative measures you need to redefine the ampere.
For example for measuring a single electron, you can use avalanche effects, which are relatively simple to realize, but would not be suitable for the quantitative approach you need to define an SI unit.
I'm not very well-informed regard quantum computing, but the problem with it seems to be more in realm of keeping the quantum states stable and controlled, and less on the measurement side.
Re: Counting Down to the New Ampere (2016)
#5So does this mean that quantum computing will become more viable? Since in quantum computing, calculations are accomplished by measuring the spin of an electron, I would imagine this would increase the throughput to a measurement instrument since this is allowing one electron to pass at a faster pace. While electron measurement instruments still need to be advanced significantly, I would imagine an innovation like th…
I think you'd also need to redefine the meter and second to speed up light. Unfortunately, the footnote specifies that we can expect only "major changes in the kilogram, ampere, kelvin, and mole" in the new SI 2018, so it seems we'll have to wait for the release after that. On the bright side, the changes to the kilogram might begin to address the obesity crisis.
Meter is already specified by fixing the speed of light. Seconds are defined in terms of Cesium atom vibrations.
Re: Counting Down to the New Ampere (2016)
#6A mostly unrelated question, in case any metrology geeks are around: why is the Kelvin an SI unit?
Naively, there seem to be multiple approaches to derive temperature from other, more fundamental units. Like using the thermodynamic definition, 1/T = dS/dE, or using Boltzmann's law to approach temperature from the mean kinetic energy of gas particles. Are none of them suitable for precise measurement?
Re: Counting Down to the New Ampere (2016)
#7A mostly unrelated question, in case any metrology geeks are around: why is the Kelvin an SI unit? Naively, there seem to be multiple approaches to derive temperature from other, more fundamental units. Like using the thermodynamic definition, 1/T = dS/dE, or using Boltzmann's law to approach temperature from the mean kinetic energy of gas particles. Are none of them suitable for precise measurement?
It's not really possible to derive temperature from other more fundamental units. For example, you can't define entropy as an absolute number; it needs to be assigned a unit, and the standard way of doing this is to multiply it by the Boltzmann constant, which depends on a unit of temperature. The mean kinetic energy of gas particles (3/2 kT) also depends on the Boltzmann constant.
Re: Counting Down to the New Ampere (2016)
#8A mostly unrelated question, in case any metrology geeks are around: why is the Kelvin an SI unit? Naively, there seem to be multiple approaches to derive temperature from other, more fundamental units. Like using the thermodynamic definition, 1/T = dS/dE, or using Boltzmann's law to approach temperature from the mean kinetic energy of gas particles. Are none of them suitable for precise measurement?
One answer is that there are SI units for a lot of derived units. A Watt is Joule/second, for example. But that's not what you're really asking.
Kelvin is considered one of the 7 base SI units, as described here: http://physics.nist.gov/cuu/Units/units.html
I think the mean kinetic energy of gas particles is impossible to measure directly. You can compute it by measuring the temperature though :)
Re: Counting Down to the New Ampere (2016)
#9Earlier quoted context omitted.
I think you'd also need to redefine the meter and second to speed up light. Unfortunately, the footnote specifies that we can expect only "major changes in the kilogram, ampere, kelvin, and mole" in the new SI 2018, so it seems we'll have to wait for the release after that. On the bright side, the changes to the kilogram might begin to address the obesity crisis.
Meter is already specified by fixing the speed of light. Seconds are defined in terms of Cesium atom vibrations.
> Seconds are defined in terms of Cesium atom vibrations.
Not vibrations of the atoms themselves. The second is defined in terms of the period of the radiation corresponding to a particular hyperfine transition of the Cesium atom.
Re: Counting Down to the New Ampere (2016)
#10Does anyone know why these apparatuses are usually "inverted", i.e. hang from the ceiling. I've seen the same thing for quantum computers. Is it related to the way they are cooled? Or is it easier to work with somehow?