ATOMIC CLOCK
First Claim
1. An apparatus comprising:
- a condensed matter medium comprising at least one system that has at least a pair of states, said states comprising a first state and a second state with respective energy levels, said energy levels having an energy difference therebetween, wherein the energy difference varies as a function of applied magnetic field;
a magnet device arranged to apply an adjustable magnetic field to the medium;
an excitation device arranged to cause the at least one system to undergo transitions between said pair of states; and
a detection device arranged to detect the response of the at least one system induced by the excitation device and to produce an output; and
a controller for receiving the output of the detection device and arranged to control the magnet device such that the magnetic field applied to the medium has a value at which the rate of change of said energy difference with change in magnetic field is substantially zero, and to derive oscillations at a frequency determined by the energy difference between said pair of states between which the at least one system is caused to undergo transitions.
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Accused Products
Abstract
An atomic clock comprises endohedral fullerene systems which provide the standard frequency oscillations. A magnet device applies a magnetic field to the endohedral fullerenes. The applied magnetic field is adjustable. An excitation device both excites each endohedral fullerene system to cause it to undergo transitions which generate the time-keeping oscillations, and also probes the systems such that the oscillations can be measured and the device controlled. A detection device senses the response of the systems induced by the excitation device. The output of the detection device is fed to a controller. The controller produces the atomic clock output, which is the clock signal or frequency standard, and also controls the magnet device and the excitation device. The controller controls the magnetic field applied by the magnet device such that the energy difference of the time-keeping transition is insensitive to variations in magnetic field, thereby stabilizing the frequency of the oscillations and avoiding the effects of changes in external magnetic field.
31 Citations
19 Claims
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1. An apparatus comprising:
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a condensed matter medium comprising at least one system that has at least a pair of states, said states comprising a first state and a second state with respective energy levels, said energy levels having an energy difference therebetween, wherein the energy difference varies as a function of applied magnetic field; a magnet device arranged to apply an adjustable magnetic field to the medium; an excitation device arranged to cause the at least one system to undergo transitions between said pair of states; and a detection device arranged to detect the response of the at least one system induced by the excitation device and to produce an output; and a controller for receiving the output of the detection device and arranged to control the magnet device such that the magnetic field applied to the medium has a value at which the rate of change of said energy difference with change in magnetic field is substantially zero, and to derive oscillations at a frequency determined by the energy difference between said pair of states between which the at least one system is caused to undergo transitions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification