Active stabilization of coherent controllers using nearby qubits
Aspects of the present disclosure describe techniques that involve an active stabilization of coherent controllers using nearby qubits. In an aspect, a quantum information processing (QIP) system for stabilizing phase damping in qubits is described that provides a first and a second qubit ion, measuring magnetic field fluctuations using the second qubit ion, and generates one or more magnetic fields based on the measured magnetic field fluctuations, the one or more magnetic fields being applied near the first qubit ion to cancel the magnetic field fluctuations to stabilize the phase damping of the first qubit ion. Another such QIP system performs provides a first and a second qubit ion, locks a local oscillator to a frequency reference associated with the second qubit ion, and tracks, using the local oscillator, a frequency of the first qubit ion based on the frequency reference. Methods associated with these QIP systems are also described.
1 . A trapped ion quantum information processing (QIP) system comprising:
at least one ion trap including at least one first qubit ion and at least one second qubit ion; and
a local oscillator that is locked to a frequency reference associated with the at least one second qubit ion, the local oscillator being configured to track a frequency of the at least one first qubit ion based on the locked frequency reference.
2 . The trapped ion QIP system of claim 1 , wherein the at least one first qubit ion and the at least one second qubit ion have a same atomic hyperfine structure.
3 . The trapped ion QIP system of claim 1 , wherein the at least one first qubit ion and the at least one second qubit ion are different ion species.
4 . The trapped ion QIP system of claim 1 , wherein the at least one first qubit ion and the at least one second qubit ion have atomic hyperfine structures and are addressable with different wavelengths of light.
5 . The trapped ion QIP system of claim 1 , wherein the at least one first qubit ion is made from 171 Yb + and the at least one second qubit ion is made from 133 Ba + .
6 . The trapped ion QIP system of claim 1 , wherein the at least one first qubit ion and the at least one second qubit ion are close to each other in the at least one ion trap and experience substantially a same environmental fluctuations.
7 . The trapped ion QIP system of claim 1 , further comprising:
a stabilizer configured to measure magnetic field fluctuations using the at least second qubit ion, and generate one or more magnetic fields based on the measured magnetic field fluctuations; and
coils configured to apply the one or more magnetic fields applied near the at least one first qubit ion to cancel the magnetic field fluctuations.
8 . The trapped ion QIP system of claim 7 , wherein the one or more magnetic fields are generated based on the measured magnetic field fluctuations by a canceling magnetic field generation component in the stabilizer.
9 . The trapped ion QIP system of claim 7 , wherein the magnetic field fluctuation is measured using the at least second qubit ion by a local magnetic field measurement component in the stabilizer.
10 . The trapped ion QIP system of claim 1 , wherein the local oscillator is a radio frequency (RF) oscillator.
11 . A method for stabilizing phase damping in qubits, comprising:
providing at least one first qubit ion and at least one second qubit ion;
locking a local oscillator to a frequency reference associated with the at least one second qubit ion; and
tracking, using the local oscillator, a frequency of the at least one first qubit ion based on the locked frequency reference.
12 . The method of claim 11 , wherein the at least one first qubit ion and the at least one second qubit ion have a same atomic hyperfine structure.
13 . The method of claim 11 , wherein the at least one first qubit ion and the at least one second qubit ion are different ion species.
14 . The method of claim 11 , wherein the at least one first qubit ion and the at least one second qubit ion have atomic hyperfine structures and are addressable with different wavelengths of light.
15 . The method of claim 11 , wherein the at least one first qubit ion is made from 171 Yb + and the at least one second qubit ion is made from 133 Ba + .
16 . The method of claim 11 , wherein the at least one first qubit ion and the at least one second qubit ion are close to each other in at least one ion trap and experience substantially a same environmental fluctuations.
17 . The method of claim 11 , further comprising:
measuring magnetic field fluctuations using the at least second qubit ion; and
generating one or more magnetic fields based on the measured magnetic field fluctuations, wherein the one or more magnetic fields are being applied near the at least one first qubit ion to cancel the magnetic field fluctuations.
18 . The method of claim 17 , wherein the one or more magnetic fields are generated based on the measured magnetic field fluctuations by a canceling magnetic field generation component in the stabilizer.
19 . The method of claim 17 , wherein the magnetic field fluctuation is measured using the at least second qubit ion by a local magnetic field measurement component in the stabilizer.
20 . The method of claim 11 , wherein the local oscillator is a radio frequency (RF) oscillator.