We present a time-resolved digital quantum simulation of cosmological particle creation in a de Sitter–radiation transition in a Friedmann–Lemaître–Robertson–Walker (FLRW) spacetime. Instead of compiling only the final Bogoliubov transformation into a one-shot circuit, we discretize the conformal-time evolution and implement the dynamics as a Trotterized sequence of short-time circuit blocks. This formulation gives access not only to the late-time particle number, but also to the build-up of fixed-basis pair occupation during the nonadiabatic transition. Using a four-qubit single-excitation encoding for a momentum pair $(+\mathbf{k},-\mathbf{k})$, we compare matrix-Trotter evolution, noiseless statevector simulation, finite-shot Qiskit Aer simulation, and a shallow $N=1$ IBM hardware implementation. The simulator results are consistent with the analytic sudden-transition benchmark $n_k=1/[4(k{\eta }_e{)}^4]$ in the controlled single-excitation regime. The IBM experiment demonstrates execution of the shallow circuit block, but exhibits a residual hardware error of order ${10}^{-2}$, indicating that quantitative hardware reconstruction of the particle spectrum remains beyond current noisy intermediate-scale quantum (NISQ) performance.

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• Particle production
• Quantum computing models
• Quantum cosmology
• Quantum fields in curved spacetime
• Quantum software