Laser cooling atomic objects with phonon pumping
A method of performing a quantum gate operation in an ion trap quantum computing system includes identifying one or more error mechanisms that cause a quantum computational error in a quantum gate operation on a first trapped ion of an ion chain comprising a plurality of trapped ions, wherein the quantum gate operation is performed by applying a first Raman laser beam and a second Raman laser beam, computing a first amplitude of the first Raman laser beam, and a second amplitude of the second Raman laser beam such that the effect of the identified one or more error mechanisms is accounted for, and applying the first Raman laser beam having the computed first amplitude and the second Raman laser beam having the computed second amplitude on the first trapped ion to perform the quantum gate operation on the first trapped ion.
1 . A method for cooling an atomic object, comprising:
controlling one or more voltage sources to cause a confinement apparatus to confine the atomic object at a position defined by the confinement apparatus, the confinement apparatus comprises (a) one or more radio frequency (RF) electrodes defining an RF null axis of the confinement apparatus and (b) a plurality of control electrodes, wherein the atomic object comprises at least two quantum objects, the at least two quantum objects comprising a first component of a first species of the at least two quantum objects and a second component of a second species of the at least two quantum objects, wherein motion of the atomic object at the position defined by the confinement apparatus comprises contributions from one or more radial motional modes of the atomic object and contributions from one or more axial motional modes of the atomic object;
causing at least one first control signal to be provided to at least one control electrode of the plurality of control electrodes, wherein the at least one first control signal causes the at least one control electrode to generate an oscillating potential at the position defined by the confinement apparatus and configured to cause at least one radial motional mode of the one or more radial motional modes of the atomic object to couple to at least one axial motional mode of the one or more axial motional modes of the atomic object or cause two radial motional modes of the atomic object to couple to each other such that motional energy is transferred from the at least one radial motional mode to the at least one axial motional mode or between the two radial motional modes, the two radial motional modes are perpendicular to each other, and the oscillating potential has a frequency that equals a frequency difference between the at least one radial motional mode and the at least one axial motional mode or a frequency difference between the two radial motional modes; and
controlling one or more manipulation sources to cause cooling signals to be incident on the atomic object, wherein the at least one radial motional mode is dominated by motion of the first component of the first species of the at least two quantum objects and the cooling signals are tuned to cause cooling of the second component of the second species of the at least two quantum objects.
2 . The method of claim 1 , wherein the at least one radial motional mode of the one or more radial motional modes of the atomic object are dominated by the first species of the atomic object and the at least one axial motional mode of the one or more axial motional modes of the atomic object are dominated by the second species of the atomic object.
3 . The method of claim 1 , wherein the first species of the at least two quantum objects is configured for use as a coolant ion in a sympathetic cooling scheme for the atomic object.
4 . The method of claim 1 , wherein the first species quantum object is a Yb ion, and the second species quantum object is an Ba ion.
5 . The method of claim 1 , wherein the oscillating potential is a pulse oscillating potential, which is configured to cause the at least one radial motional mode of the one or more radial motional modes of the atomic object to couple to the at least one axial motional mode of the one or more axial motional modes of the atomic object for a predetermined period.
6 . The method of claim 5 , wherein a sequence of causing the at least one first control signal to be provided to the at least one control electrode of the plurality of control electrodes and controlling the one or more manipulation sources to cause the cooling signals to be incident on the atomic object are performed repeatedly until a threshold temperature is achieved for the atomic object.
7 . The method of claim 1 , wherein the oscillating potential is a continuous oscillating potential, which is configured to cause the at least one radial motional mode of the one or more radial motional modes of the atomic object and the at least one axial motional mode of the one or more axial motional modes of the atomic object to hybridize.
8 . The method of claim 7 , wherein the at least one radial motional mode of the one or more radial motional modes of the atomic object and the at least one axial motional mode of the one or more axial motional modes of the atomic object are cooled at a same rate in response to the cooling signals being tuned to cause cooling of the second component of the second species of the at least two quantum objects.
9 . The method of claim 7 , wherein controlling the one or more manipulation sources to cause the cooling signals to be incident on the atomic object and causing the at least one first control signal to be provided to the at least one control electrode of the plurality of control electrodes are performed simultaneously.
10 . The method of claim 7 , wherein controlling the one or more manipulation sources to cause the cooling signals to be incident on the atomic object and causing the at least one first control signal to be provided to the at least one control electrode of the plurality of control electrodes are performed until a threshold temperature is achieved for the atomic object.
11 . An apparatus comprising at least one processor and memory storing computer-executable instructions, the computer-executable instructions configured to, when executed by the at least one processor, cause the apparatus to at least:
control one or more voltage sources to cause a confinement apparatus to confine an atomic object at a position defined by the confinement apparatus, the confinement apparatus comprises (a) one or more radio frequency (RF) electrodes defining an RF null axis of the confinement apparatus and (b) a plurality of control electrodes, wherein the atomic object comprises at least two quantum objects, the at least two quantum objects comprising a first component of a first species of the at least two quantum objects and a second component of a second species of the at least two quantum objects, wherein motion of the atomic object at the position defined by the confinement apparatus comprises contributions from one or more radial motional modes of the atomic object and contributions from one or more axial motional modes of the atomic object;
cause at least one first control signal to be provided to at least one control electrode of the plurality of control electrodes, wherein the at least one first control signal causes the at least one control electrode to generate an oscillating potential at the position defined by the confinement apparatus and configured to cause at least one radial motional mode of the one or more radial motional modes of the atomic object to couple to at least one axial motional mode of the one or more axial motional modes of the atomic object or cause two radial motional modes of the atomic object to couple to each other such that motional energy is transferred from the at least one radial motional mode to the at least one axial motional mode or between the two radial motional modes, the two radial motional modes are perpendicular to each other, and the oscillating potential has a frequency that equals a frequency difference between the at least one radial motional mode and the at least one axial motional mode or a frequency difference between the two radial motional modes; and
control one or more manipulation sources to cause cooling signals to be incident on the atomic object, wherein the at least one radial motional mode is dominated by motion of the first component of the first species of the at least two quantum objects and the cooling signals are tuned to cause cooling of the second component of the second species of the at least two quantum objects.
12 . The apparatus of claim 11 , wherein the at least one radial motional mode of the one or more radial motional modes of the atomic object are dominated by the first species of the atomic object and the at least one axial motional mode of the one or more axial motional modes of the atomic object are dominated by the second species of the atomic object.
13 . The apparatus of claim 11 , wherein the first species of the at least two quantum objects is configured for use as a coolant ion in a sympathetic cooling scheme for the atomic object.
14 . The apparatus of claim 11 , wherein the first species quantum object is a Yb ion, and the second species quantum object is an Ba ion.
15 . The apparatus of claim 11 , wherein the oscillating potential is a pulse oscillating potential, which is configured to cause the at least one radial motional mode of the one or more radial motional modes of the atomic object to couple to the at least one axial motional mode of the one or more axial motional modes of the atomic object for a predetermined period.
16 . The apparatus of claim 15 , wherein a sequence of causing the at least one first control signal to be provided to the at least one control electrode of the plurality of control electrodes and controlling the one or more manipulation sources to cause the cooling signals to be incident on the atomic object are performed repeatedly until a threshold temperature is achieved for the atomic object.
17 . The apparatus of claim 11 , wherein the oscillating potential is a continuous oscillating potential, which is configured to cause the at least one radial motional mode of the one or more radial motional modes of the atomic object and the at least one axial motional mode of the one or more axial motional modes of the atomic object to hybridize.
18 . The apparatus of claim 17 , wherein the at least one radial motional mode of the one or more radial motional modes of the atomic object and the at least one axial motional mode of the one or more axial motional modes of the atomic object are cooled at a same rate in response to the cooling signals being tuned to cause cooling of the second component of the second species of the at least two quantum objects.
19 . The apparatus of claim 17 , wherein controlling the one or more manipulation sources to cause the cooling signals to be incident on the atomic object and causing the at least one first control signal to be provided to the at least one control electrode of the plurality of control electrodes are performed simultaneously.
20 . The apparatus of claim 17 , wherein controlling the one or more manipulation sources to cause the cooling signals to be incident on the atomic object and causing the at least one first control signal to be provided to the at least one control electrode of the plurality of control electrodes are performed until a threshold temperature is achieved for the atomic object.