I had recently attended the Grace Hopper 2019 conference in Orlando, and had the opportunity to speak with researchers from IBMQ and Qiskit about the current state of quantum computing. Although, I did not get a chance to obtain a ticket to IBMQ's Universal Studios event at The Wizarding World of Harry Potter (the line was extremely long!), I still wanted to share some of the topics surrounding the emerging tech of quantum computing.
I spoke with Cihan Kurter, Research Scientist at IBM Watson, after her presentation titled, "Near-Term Applications of Quantum Computers", and asked, how exactly does the mysterious IBMQ qubit work?
IBMQ creates a qubit from a junction, which consists of two superconducting filaments with a gap between them. In effect, each qubit is a circuit. The entire IBMQ machine holds many of these circuits, and thus, many qubits. You can see a picture of just how large IBMQ is, in the above images. The bulk of such a large machine is for cooling the junctions down to near absolute zero temperature (0.015 Kelvin), in order to reduce error rates due to decoherence.
At the initial resting state, the qubit corresponds to a value of 0. To set the qubit to a value of 1, a microwave is applied to the junction.
We're all familiar with microwaves that cook our dinner, and so, an initial thought might be that a huge microwave is being applied to all qubit circuits across the entire IBMQ machine. How else would you apply a microwave?
However, microwaves are actually fired through a tiny tube directly into the junction. Each qubit has its own tube for directed microwaves and each qubit has its own junction. The microwave energizes the junction, causing the effect of quantum tunneling between the filaments, and resulting in an excited state of the qubit and a value of 1. To adjust the qubit state to a value between 0 or 1, the frequency of the microwave is lowered or raised.
During my own experimentation with quantum computers, I've noticed delay times between 30 seconds and up to several minutes when running quantum computing programs on the IBMQ platform. However, surely most of this time is due to wait times in the queue for processing.
I spoke with Sarah Sheldon, Research Staff Member at IBM Watson, and confirmed that the majority of the time for executing a quantum program, indeed, comes from the wait times for accessing IBMQ's machines. Additionally, each measurement of a qubit requires a complete tear-down, setup, and execution of the physical test. Each test, itself, takes a few milliseconds to execute, with a total time of several seconds (including the network API request from Qiskit to IBMQ's servers). However, IBM has recently put an additional machine online, which should help with the queue times.
In summary, quantum computing is very much still in the research phase. Within the next 3-5 years, we may see applications of quantum computing, using hybrid quantum and classical algorithms, being used to simulate chemicals (such as the caffeine molecule), and other applications. However, error correction and qubit architecture remain much of the challenge.
