Laser on-demand scrambling of two-level systems in superconducting qubits
Methods and systems for mitigating the effects of defects in a quantum processor are provided. A mitigation system uses an iterative process of applying light pulses and examining qubit relaxation times to eliminate or minimize two-level system (TLS) interaction with qubits. The system applies a first light pulse to illuminate a quantum processor having one or more qubits. The system receives qubit relaxation times that are measured at different electric field frequencies after applying the first light pulse. The system applies a second light pulse to illuminate the quantum processor upon determining that the received qubit relaxation times indicates presence of a strongly coupled TLS in the quantum processor.
1 . A method comprising:
applying a first light pulse to illuminate a quantum processor comprising one or more qubits;
receiving qubit relaxation times that are measured at different qubit frequencies after applying the first light pulse; and
applying a second light pulse to illuminate the quantum processor upon determining that the received qubit relaxation times indicates presence of a strongly coupled two-level system (TLS) in the quantum processor, wherein the presence of strongly coupled TLS in the quantum processor is indicated by a received qubit relaxation time being less than a threshold ratio of an expected qubit relaxation time at a frequency of interest.
2 . The method of claim 1 , wherein at least one of the first or second the light pulses scrambles a frequency landscape of the TLSs, the frequency landscape comprising the received qubit relaxation times measured at different qubit frequencies.
3 . The method of claim 1 , wherein the threshold ratio is 0.75.
4 . The method of claim 1 , further comprising receiving performance parameters of one or more qubits in the quantum processor to identify a qubit that fails to meet a performance threshold, wherein the received qubit relaxation times comprises relaxation times of the identified qubit.
5 . The method of claim 4 , wherein the first and second light pulses are local to the identified qubit.
6 . The method of claim 1 , wherein the first and second light pulses are global to the quantum processor and illuminate multiple qubits in the quantum processor.
7 . A computer program product comprising:
one or more non-transitory computer-readable storage devices and program instructions stored on at least one of the one or more non-transitory storage devices, the program instructions executable by a processor, the program instructions comprising sets of instructions for:
applying a first light pulse to illuminate a quantum processor comprising one or more qubits;
receiving qubit relaxation times that are measured at different qubit frequencies after applying the first light pulse; and
applying a second light pulse to illuminate the quantum processor upon determining that the received qubit relaxation times indicates presence of a strongly coupled two-level system (TLS) in the quantum processor, wherein the presence of strongly coupled TLS in the quantum processor is indicated by a received qubit relaxation time being less than a threshold ratio of an expected qubit relaxation time at a frequency of interest.
8 . The computer program product of claim 7 , wherein at least one of the first or second light pulses is used to scramble a frequency landscape of the TLSs, the frequency landscape comprising the received qubit relaxation times measured at different qubit frequencies.
9 . The computer program product of claim 7 , wherein the threshold ratio is 0.75.
10 . The computer program product of claim 7 , wherein the sets of instructions further comprise receiving performance parameters of one or more qubits in the quantum processor to identify a qubit that fails to meet a performance threshold, wherein the received qubit relaxation times comprises relaxation times of the identified qubit.
11 . The computer program product of claim 10 , wherein the first and second light pulses are local to the identified qubit and illuminate only the identified qubit and no other qubit.
12 . The computer program product of claim 7 , wherein the first and second light pulses are global to the quantum processor and illuminate multiple qubits in the quantum processor.
13 . A system comprising:
a quantum processor comprising one or more qubits;
a two-level system (TLS) mitigation controller configured to perform acts comprising:
applying a first light pulse to illuminate a quantum processor comprising one or more qubits;
receiving qubit relaxation times that are measured at different qubit frequencies after applying the first light pulse; and
applying a second light pulse to illuminate the quantum processor upon determining that the received qubit relaxation times indicates presence of a strongly coupled TLS in the quantum processor, wherein the presence of strongly coupled TLS in the quantum processor is indicated by a received qubit relaxation time being less than a threshold ratio of an expected qubit relaxation time at a frequency of interest.
14 . The system of claim 13 , wherein at least one of the first or second the light pulses is used to scramble a frequency landscape of the TLS in the quantum processor, the frequency landscape comprising the received qubit relaxation times measured at different qubit frequencies.
15 . The system of claim 13 , wherein the threshold ratio is 0.75.
16 . The system of claim 13 , wherein the acts further comprise receiving performance parameters of one or more qubits in the quantum processor to identify a qubit that fails to meet a performance threshold, wherein the received qubit relaxation times comprises relaxation times of the identified qubit.
17 . The system of claim 16 , wherein the first and second light pulses is local to the identified qubit and illuminate only the identified qubit and no other qubit.
18 . The system of claim 13 , wherein the first and second light pulses are global to the quantum processor and illuminate multiple qubits in the quantum processor.
19 . A method comprising:
providing a quantum processor comprising one or more qubits;
configuring a two-level system (TLS) mitigation controller to perform acts comprising:
applying a first light pulse to illuminate a quantum processor comprising one or more qubits;
receiving qubit relaxation times that are measured at different electric field frequencies after applying the first light pulse; and
applying a second light pulse to illuminate the quantum processor upon determining that the received qubit relaxation times indicates presence of a strongly coupled TLS in the quantum processor wherein the presence of strongly coupled TLS in the quantum processor is indicated by a received qubit relaxation time being less than a threshold ratio of an expected qubit relaxation time at a frequency of interest.
20 . The method of claim 19 , wherein the threshold ratio is 0.75.
21 . The method of claim 19 , wherein the acts further comprise receiving performance parameters of one or more qubits in the quantum processor to identify a qubit that fails to meet a performance threshold, wherein the received qubit relaxation times comprises relaxation times of the identified qubit.