Accelerator Considerations of Large Circular Colliders

As we consider the tremendous physics reaches of the big future circular electron–positron and proton–proton colliders, it might be advisable to keep a close track of what accelerator challenges they face. Good progresses are being made, and yet it is reported here that substantial investments in funding, manpower, as well as a long sustained time to the R&D efforts will be required in preparation to realize these dream colliders.