Is there a way to define operators in C++? (or another language)

Question

I am aware about operator overloading, but this is not what I am talking about.

I do quite a bit of scientific computation in C++. So for example I have to compute gradients, dot products, laplacians, hessians...

All of these usually have well defined and standrad math symbols. The gradient uses nabla, the hessian nabla^2 the laplacian \delta ...

I normally have to write vec Gradient(fun_ptr) or Hessian(fun_ptr).

The issues is that this makes the code deviate from the paper I am implementing and it makes it just a little harder to catch when you copied something wrong.

Is there any way to define the \nabla character as an operator for example?