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Nuclear clocks might soon rival the best atomic ones as supremely accurate timekeepers — a testament to the value of both competition and cooperation in research.
What do you get when you put a nuclear physicist, an optical physicist and a crystal-growing maestro together in a laboratory? This is not the beginning of a bad joke, but the starting point for making what could become the world’s most accurate timepiece. The level of boundary-crossing innovation required to make a nuclear clock serves as an example of how cooperation can exist alongside competition in science.
Atomic clocks currently hold the world record for most accurate timekeeping. They tick out time through the frequency of light emitted and absorbed by electrons jumping between atomic energy levels. Lasers that are locked to a clock’s frequency provide the read-out.
Nuclear clocks, by contrast, tap into the energy shifts of protons and neutrons inside an atom’s nucleus. These energy transitions occur at a higher frequency than do those of electrons, making for a faster tick that could someday slice time more finely than atomic clocks can. And nuclear clocks come with other benefits. They are inherently more robust than atomic ones, because the nucleus and its energy transitions are more impervious to external perturbations than orbiting atomic electrons are. The transitions are also more heavily influenced by constants of nature, such as the strength of the strong nuclear force. This makes nuclear clocks highly sensitive instruments for testing fundamental physics. But nuclear clocks are also difficult to make, which is why it has taken almost 50 years to get close to a working model. For most atoms, a huge amount of energy is needed to lift the nucleus away from its lowest energy state, well beyond what can be achieved using precise, stable probing lasers.
What do you get when you put a nuclear physicist, an optical physicist and a crystal-growing maestro together in a laboratory? This is not the beginning of a bad joke, but the starting point for making what could become the world’s most accurate timepiece. The level of boundary-crossing innovation required to make a nuclear clock serves as an example of how cooperation can exist alongside competition in science.
Atomic clocks currently hold the world record for most accurate timekeeping. They tick out time through the frequency of light emitted and absorbed by electrons jumping between atomic energy levels. Lasers that are locked to a clock’s frequency provide the read-out.
Nuclear clocks, by contrast, tap into the energy shifts of protons and neutrons inside an atom’s nucleus. These energy transitions occur at a higher frequency than do those of electrons, making for a faster tick that could someday slice time more finely than atomic clocks can. And nuclear clocks come with other benefits. They are inherently more robust than atomic ones, because the nucleus and its energy transitions are more impervious to external perturbations than orbiting atomic electrons are. The transitions are also more heavily influenced by constants of nature, such as the strength of the strong nuclear force. This makes nuclear clocks highly sensitive instruments for testing fundamental physics. But nuclear clocks are also difficult to make, which is why it has taken almost 50 years to get close to a working model. For most atoms, a huge amount of energy is needed to lift the nucleus away from its lowest energy state, well beyond what can be achieved using precise, stable probing lasers.
Progress on nuclear clocks shows the benefits of escaping from scientific silos
Nuclear clocks might soon rival the best atomic ones as supremely accurate timekeepers — a testament to the value of both competition and cooperation in research.
www.nature.com