Superconducting vs trapped ion quantum computing
There are many types of quantum computers, all with their own advantages and disadvantages. Each using a different approach to the underlying architecture in an attempt to achieve a universal quantum computer. The race has been on for some time, but as the focus shifts from predominantly being university and government funded, private organizations are now participating.
A qubit is likened to the central processing unit (CPU) for a quantum computer, its the underlying component that allows a quantum computer to perform at unthinkable speeds. While quantum computers don’t have a CPU seen in classical computers, the qubit is effectively an atom that is manipulated by a vacuum.
Physical attribute of a qubit
Quantum physics covers a broad spectrum and so do qubits, depending on the research facility and their approach to developing quantum computers, the underlying architecture will differ.
There are many advantages and disadvantages between each method, some targeting a very specific problem where a certain type of qubit has proven to deliver the best results.
Lets start with superconducting quantum computers.
Superconducting (transmon-qubits)
Superconducting quantum computers are probably most widely publicised due to their space age looking design. Gold plates and tubing looking like a designer chandelier.
Pros
- Considerable research has been undertaken by research facilities over an extended period.
- Proven stability with the qubit, reducing noise and interference
- Providing consistent results and allowing organisations to interact with the platform in early development stages
- Cooling technology becoming more widely available as private companies identifying the opportunity and growing or entering the dilution refrigerator segment
- Fast gate times in nanosecond range
Cons
- Requirement for complex dilution refrigerator to keep components at extremely cold operating conditions.
- Energy required to cool the quantum computer
- Specialised facilities required to support the entire quantum computer.
- Ability to manufacture at scale also has been limited and no indication of change.
- Reduced coherence times compared to Trapped Ions
Trapped Ion
Trapped Ion quantum computers are less seen in the media, but have started to get interest over the past 2-3 years. The qubit is based on ion traps which are electromagnetic fields that spatially fix charge particles allowing for overall controlled movement.
Pros
- Ability to operate at temperatures that do not required complex and expensive refrigeration
- Coherence time is considerable longer than superdoncuting
- Some vendors are already engaged with large public companies to deliver proof of concept systems.
- Reduced gate errors (delivers better performance and outcome)
- Some research suggests trapped ions interact better with others ions, which makes it easier to run some complex calculations.
Cons
- Slower gate times (however some will argue less errors)
- Less widely used that other architectures
- Ability to scale up may be limited according to some research.
Conclusions
While it’s nearly impossible to compare superconducting against trapped ions, what we can do is look at the capability of each system which helps demonstrate key characteristics that should be considered depending on the associated use case.
The outcome will change as development continues, but for now, depending on your use case, and my other factors related to running a quantum computer, it’s not possible to rule out one approach over anoth
