No, that's not true at all. For example, a chemistry simulation can be done in first quantization; where the state is a list of superposed 2s-complement integ

No, that's not true at all. For example, a chemistry simulation can be done in first quantization; where the state is a list of superposed 2s-complement integers indicating the positions of the electrons (as opposed to a more direct one-qubit=one-position mapping). And the list is initialized in a way that satisfies the Pauli exclusion principle by using a sorting network [1]. This is presumably not at all how Nature does it. Another example is factoring. Shor's factoring algorithm is not at all like behaving analogous to a physical system. It's about modular exponentiation and Fourier transforms; math things not physics things. Yet another example is Hamming weight phasing. If you need to rotate many qubits by a common angle around the Z axis, you can achieve that effect more cheaply by temporarily computing their Hamming weight (under superposition) and then rotating the first qubit of the Hamming weight register by the angle, the second by twice the angle, the third by four times the angle, etc. And actually that various-rotation-angles operation can then also be replaced by an addition into a special reusable phase gradient state; this achieves the desired effect by phase kickback [2]. Adding the Hamming weight of their spins into a helper state is probably not how Nature goes about precessing electrons in a uniform magnetic field. [1]: https://arxiv.org/abs/1711.10460 https://arxiv.org/abs/1711.10460 [2]: https://arxiv.org/abs/1709.06648 https://arxiv.org/abs/1709.06648