Figure 9 shows an exemplary two-dimensional array of qubits 900 receiving RF pulse signals, according to one embodiment. Each of the dark circles denoted by numbers 1-5 represent a qubit. As depicted, each of the qubits are weakly coupled (i.e., reactively) by quantum communication (QC) links QCL. The QC links links QCL may include superconductive electrical links formed from, for example, Aluminum (Al) or Niobium (Nb), whereby each QC link QCL may be reactively coupled (e.g., capacitively) to a qubit at each end. The QC links links QCL provide a means for enabling quantum entanglement conditions between the qubits in the array. As shown, qubits 1 are coupled to transmission line TL1 and are driven at a frequency F1, qubits 2 are coupled to transmission line TL2 and are driven at a frequency F2, qubits 3 are coupled to transmission line TL3 and are driven at a frequency F3, qubits 4 are coupled to transmission line TL4 and are driven at a frequency F4, qubits 5 are coupled to transmission line TL5 and are driven at a frequency F5, and qubits 1 are coupled to transmission line TL'1 and are also driven at frequency F1. In a serpentine connection approach, transmission lines that carry the same frequency to the qubits may be connected together. For example, transmission lines TL1 and TL'1 are both driven at the same frequency F1, and are thus connected together, as indicated by dashed line connection 908. Although for illustrative brevity, only transmission lines TL1 and TL'1 are shown, additional transmission lines coupled to other qubits 1 in the exemplary two-dimensional array of qubits 900 would also follow a serpentine pattern of connections. The same rationale may be applied to transmission lines TL2-TL5.
Alternatively, connections such as connection 908 may be omitted in favor of, for example, inductively coupling a frequency source to transmission lines being driven by the same frequency pulse signal. For example, transmission lines TL1 and TL'1 are both driven at the same frequency F1. Therefore, the RF output signal from a single RF source 904 (i.e., signal generator) may be inductively coupled to each of the transmission lines TL1, TL'1 that are driven at the same frequency F1. In particular, inductive coupling device a 904 couples the RF output signal from RF source 904 to transmission lines TL1, while inductive coupling device b 906 couples the RF output signal from RF source 904 to transmission lines TL'1. The same rationale may be applied to transmission lines TL2-TL5. The qubits 1-5 depicted in exemplary two-dimensional array of qubits 900 may include the same or similar circuitry for receiving an attenuated RF pulse signal as those corresponding to system 100 of Figure 1.
The above exemplary two-dimensional array of qubits 900 of qubits 1-5 may be utilized to form, among other things, a surface code method of error prevention/correction using a discrete number of frequencies, pulse shapes, and phases. For example, one approach may contemplate using five (5) different qubit frequencies (i.e., F1-F5), and six (6) or more different pulses (e.g., pulse period, pulse interval, etc.) associated with each frequency. It may be appreciated that the depicted 2D mesh is exemplary. Thus, different lattices with different interconnections of the qubits and a different numbers of frequencies can be utilized.
The two-dimensional array of qubits 900 may be maintained at cryogenic temperatures below one hundred (100) millikelvins (mK) in order to maintain the array 900 at superconducting temperatures. For example, the two-dimensional array of qubits 900 may be cooled in a cryostat to a temperature of about 30 mK.
Although the exemplary embodiments described in the foregoing include networks of reactive components having capacitor devices, other reactive components such as inductors may also be utilized in order to provide a divider network capable of attenuating the received RF pulse signals in a controlled manner.