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Graphene and Quantum Hall Effect Could Help Redefine Metrics
eldavojohn writes "The National Physical Laboratory has published research in Nature that could lead to redefining two of our most commonly used metrics. There's been a lot of trouble stemming from defining an exact Kilogram as some lump of platinum-iridium sitting in a glass case somewhere, so the proposal was put forth to study the quantum hall effect with different materials. Enter the Nobel prize winning, super strong, silicon usurping graphene. NPL now says you can add quantum resistance metrology to the list of graphene's many conquests as they say the quantum hall effect in graphene is 'very robust and easy to measure.' With this at their disposal, the Kilogram may be redefined in terms of h, the Planck constant, and the Ampere may be redefined in terms of e, the electron charge (alias Elementary charge or the charge of a proton). You can find the full paper here."
It even won a Nobel prize.
The definition of a unit must be physically instantiable. That is, you have to be able to use the definition to build a device or artifact that can be used to calibrate a meter for said unit. Otherwise, the unit is useless.
This means that some units still have cumbersome and strange definitions, as we do not have the technology to use the obvious definitions to calibrate measurement devices.
Which is definitely silly - the base unit is charge flow, and the derived unit is charge?
Not really. Simple algebra can easily convert from one unit to another. And the second is far better defined than the Coulomb is. So there's no measurable error introduced by using the Ampere as the base unit rather than the Coulomb.
1963 when the UK parliament adopted the international definition (from 1959) of the pound as 0.45359237 kilogrammes. Ironically for you, it will change again if the definition of the kilogramme changes as per the article.
it's = it is
its = belonging to it
Right now the accuracy with which the kilogram can be measured is about 1 part per 1E8. The paper mentions a noise of around 1 part per 1.6E11. That's over 1,000 times better. That certainly suggests that this method will be sufficiently "better" to be used as the new standard.
I, for one, welcome our incredibly accurate overlords.
Great warrior...hrmph! Wars not make one great.
It even won a Nobel prize.
They only awarded that because it wasn't George Bush.
"Yay, inanimate carbon, errr, sheet!
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
If you spent the time needed for two laboratory exercises, one to prove that you had created a circuit with an Ampere of current and another to prove that you had amassed a Coulomb of charge, then you would understand why the base unit is Ampere, not Coulomb.
As a financail advisor recently pointed out.
There is no trade imbalance with China. They give us tons of wortgless goods and we give them tons of eorthless dollars.
Seems fair wen you think about it.
i thought once I was found, but it was only a dream.