What are the major obstacles in creating biologically based quantum computers, especially regarding the maintenance of coherence?

Creating biologically based quantum computers faces significant challenges, primarily centered around maintaining quantum coherence for a sufficiently long time to perform useful computations. Coherence, the ability of a quantum system to exist in a superposition of states, is essential for quantum computation. However, biological systems are inherently noisy and complex environments that promote decoherence, which is the loss of quantum coherence. One major obstacle is thermal noise. Biological systems operate at relatively high temperatures compared to the cryogenic temperatures used in many solid-state quantum computers. These higher temperatures lead to increased molecular vibrations and collisions, which disrupt the delicate quantum states of potential qubits (quantum bits). Another obstacle is the presence of a vast number of degrees of freedom in biological molecules. Proteins, DNA, and other biomolecules are large and flexible, with numerous vibrational and rotational modes that can couple to the qubits and cause decoherence. Controlling and isolating these degrees of freedom is extremely difficult. Environmental fluctuations also pose a problem. Variations in pH, ion concentrations, and other environmental factors can affect the electronic and spin properties of qubits, leading to dephasing and decoherence. Furthermore, engineering precise and controllable interactions between qubits is challenging in biological systems. Implementing quantum gates, which are the basic building blocks of quantum algorithms, requires precise control over the interactions between qubits. Creating stable and reliable quantum gates using biological molecules is a significant hurdle. Finally, scaling up the number of qubits is another challenge. Building a useful quantum computer requires a large number of qubits, but creating and maintaining coherence in a large ensemble of biological qubits is a daunting task. Therefore, the major obstacles are primarily related to maintaining coherence in the face of thermal noise, complex molecular dynamics, environmental fluctuations, and the difficulty of engineering precise qubit interactions and scaling up the system.