The Closed Room Model: A Unified Physical Mechanism for Observer-Dependent Paradoxes in Quantum Mechanics

Quantum mechanics hosts a family of paradoxes—Wigner's friend, the black hole firewall, the Frauchiger-Renner paradox, and reference-frame dependence—that all arise from conflicts between different observers' descriptions of the same physical process. We propose a unified physical mechanism, the "Closed Room" model, that traces all these paradoxes to a single physical principle: the monogamy of entanglement enforces an information blockade between observers who have not shared a direct measurement interaction in the same basis. When an observer Alice performs a direct measurement on a system S, she enters a closed room defined by her entanglement with S. Any external observer Bob, who has not performed a direct measurement on S, is physically barred by monogamy from accessing the determinate facts inside the room. Bob's only consistent description is a superposition state. We verify this prediction using a 3-qubit quantum circuit on superconducting hardware: when Bob measures in the same basis as Alice, their outcomes exhibit perfect correlation (total correlation 86% in |000⟩ and |111⟩); when Bob measures in a different basis, his outcomes are uniformly random (each ≈25%). Collapse is reconceptualized not as an objective physical event but as a perspectival shift: when Bob himself enters the room by performing a direct measurement, he switches from indirect to direct observation and thereby joins the shared reality. The Closed Room model provides a conceptually minimal, experimentally testable framework that unifies the aforementioned paradoxes and establishes basis-matching as the operational condition for observer-dependent information sharing in quantum mechanics.