Controlling alkaline earth atoms for quantum computing and metrology applications

An apparatus, comprising:

• one or more lasers emitting one or more first laser beams, one or more second laser beams, one or more third laser beams, and one or more fourth laser beams;
• a plurality of atoms, wherein:
• the one or more first laser beams generate an array of traps each including a trapping potential, each of the trapping potentials trapping a single one of the atoms, and
• each of the atoms have levels including:
• a first energy level;
• a second energy level having an energy higher than the first energy level;
• a third energy level;
• a fourth energy level higher than the first energy level and lower than the third energy level;
• and
• the one or more second laser beams irradiate the atoms so as to generate fluorescence, and the second laser beam have a frequency and a polarization tuned to excite a first transition between the first energy level and the second energy level so that the fluorescence comprises spontaneous emission from the second energy level back to the first energy level that images with single atom resolution so as to identify one of the atoms in each trap, and
• the one or more third laser beams irradiate the atoms so as to cool each of the atoms;
• and
• the one or more fourth laser beams (clock laser beams) are tuned to excite a clock transition between the first energy level and the fourth energy level;
• a detector detecting the presence or absence of the fluorescence so as to generate a signal representing a presence or absence of each of the atoms in the ground state (wherein electrons are in the first energy level) or in a clock state (wherein one of the electrons is in the fourth energy level), the detectors imaging each atom individually;
• the detector detecting the signals at plurality of times:
• (1) after the atoms are prepared in the ground state, so that absence of the fluorescence indicates the atom does not occupy the trap (first signal);
• (2) after excitation from the first energy level to the second energy level using the one or more fourth laser beams red detuned from the clock transition, so that presence of the fluorescence indicates the atom is in an excited state wherein at least one of the electrons is in the first energy level (second signal);
• (3) after the atoms are prepared in the ground state after step (2), so that absence of the fluorescence indicates the atom does not occupy its respective trap (third signal);
• (4) after excitation from the first level to the second level using the one or more fourth laser beams blue detuned from the clock transition, so that presence of the fluorescence indicates the atom is in the excited state wherein one of the electrons is in the first energy level (fourth signal);
• and
• a computer/processor generating an error signal using the signals, comprising:
• determining which of the traps are occupied;
• and
• for each of the occupied traps:
• assigning a first error if the signal after the irradiation with the one or more fourth laser beams having the red detuning is higher than the signal after the irradiation with the one or more fourth laser beams having the blue detuning, indicating the frequency of the one or more fourth laser beams should be increased to resonantly excite the clock transition,
• assigning a second error if the signal after the irradiation with the one or more fourth laser beams having the red detuning is lower than the signal after the irradiation with the one or more fourth laser beams having the blue detuning, indicating the frequency of the one or more fourth laser beams should be decreased to resonantly excite the clock transition,
• assigning a zero error if the signals after the irradiation with the one or more fourth laser beams having the red detunings and the blue detunings are the same, indicating the frequency of the one or more fourth laser beams does not need to be corrected;
• converting the error signals to one or more error corrected frequencies;
• and
• a modulator modulating the one or more fourth laser beams with the error corrected frequencies so as to resonantly excite the clock transition between the first energy level and the fourth energy level using the one or more fourth laser beams having the one or more error corrected frequencies.

A method of trapping atoms, comprising:

• (a) individually trapping one or more atoms, each of the atoms trapped in a different trapping potential or trap;
• (b) individually imaging each of the atoms;
• and
• (c) individually cooling each of the atoms, wherein each of the atoms are cooled to prevent loss (of each of the atoms from their respective trap) caused by the imaging.