A variational eigenvalue solver on a photonic quantum processor is introduced, which reduces the requirements for coherent evolution compared to the quantum phase estimation (QPE) algorithm. The approach combines a photonic quantum processor with a classical computer to calculate the ground-state molecular energy for He-H⁺. The method uses a variational algorithm to compute eigenvalues and eigenvectors of a Hamiltonian, significantly reducing the need for long coherent evolution. This approach is particularly useful for quantum chemistry problems, where the Schrödinger equation is intractable for large systems. The algorithm is demonstrated using a photonic quantum processor, which can prepare and measure arbitrary two-qubit states. The results show that the method can efficiently compute the ground-state energy of He-H⁺ with high accuracy, even in the presence of experimental noise. The approach is also shown to be scalable and efficient, with the potential to be applied to other intractable problems in quantum computing. The method uses a variational algorithm to prepare the state and compute the expectation value of the Hamiltonian, which is then optimized using a classical computer. The results demonstrate that the method can achieve high accuracy with a relatively small number of quantum operations, making it a promising approach for quantum-enhanced computation.A variational eigenvalue solver on a photonic quantum processor is introduced, which reduces the requirements for coherent evolution compared to the quantum phase estimation (QPE) algorithm. The approach combines a photonic quantum processor with a classical computer to calculate the ground-state molecular energy for He-H⁺. The method uses a variational algorithm to compute eigenvalues and eigenvectors of a Hamiltonian, significantly reducing the need for long coherent evolution. This approach is particularly useful for quantum chemistry problems, where the Schrödinger equation is intractable for large systems. The algorithm is demonstrated using a photonic quantum processor, which can prepare and measure arbitrary two-qubit states. The results show that the method can efficiently compute the ground-state energy of He-H⁺ with high accuracy, even in the presence of experimental noise. The approach is also shown to be scalable and efficient, with the potential to be applied to other intractable problems in quantum computing. The method uses a variational algorithm to prepare the state and compute the expectation value of the Hamiltonian, which is then optimized using a classical computer. The results demonstrate that the method can achieve high accuracy with a relatively small number of quantum operations, making it a promising approach for quantum-enhanced computation.