In the framework of our current understanding of physics, there is no specific quantum particle that makes up space-time. Space-time itself is considered to be a fundamental framework in which particles and fields exist and interact.
According to Albert Einstein's theory of General Relativity, space-time is a dynamic, four-dimensional fabric that can be curved and influenced by the distribution of matter and energy. It is not described in terms of discrete particles, but rather as a continuous geometric structure.
In the realm of quantum physics, the fundamental particles are typically associated with specific quantum fields, such as the electromagnetic field or the Higgs field. These particles are excitations of their respective fields. However, there is currently no known quantum field that corresponds directly to space-time itself.
Efforts to reconcile General Relativity with Quantum Field Theory and formulate a consistent theory of quantum gravity are ongoing. Several approaches, such as string theory, loop quantum gravity, and causal dynamical triangulation, propose different ways to incorporate quantum effects into the description of gravity and space-time. However, the nature of space-time at the most fundamental level and whether it is composed of specific particles or structures is still an active area of research and remains an open question in physics.