Simulating a human body at the molecular level and in real-time is an immensely complex task that would require an enormous number of qubits. The exact number of qubits needed depends on various factors, including the level of detail desired, the complexity of the molecular interactions being simulated, and the level of accuracy required.
To provide a rough estimate, let's consider that a conservative estimate for accurately simulating a single molecule would require at least one qubit per atom in that molecule. A typical protein molecule consists of hundreds or thousands of atoms, and a human body contains trillions of cells, each containing multiple molecules. If we consider a simplified model of just a few thousand protein molecules, we could potentially require millions to billions of qubits for an accurate real-time simulation.
Simulating at 2x speed would require processing twice as much information in the same amount of time. In terms of qubits, this would generally require a quantum computer with more qubits and faster gate operations to maintain the same level of accuracy. However, it is difficult to provide an exact numerical estimate for the required number of qubits without specific details about the simulation and the desired level of accuracy.
It's important to note that simulating complex biological systems at the molecular level is an active area of research, both in classical and quantum computing. While quantum computers have the potential to tackle such simulations, it is currently a significant technological challenge due to the need for large-scale, fault-tolerant quantum computers with sufficient qubit counts and low error rates. We are still some distance away from achieving the necessary computational power to simulate a human body at the molecular level in real-time with quantum computers.