The notion of "closed systems" in Quantum Mechanics is discussed. For this purpose, we study two models of a quantum mechanical system P spatially far separated from the "rest of the universe" Q. Under reasonable assumptions on the interaction between P and Q, we show that the system P behaves as a closed system if the initial state of P a Q belongs to a large class of states, including ones exhibiting entanglement between P and Q. We use our results to illustrate the non-deterministic nature of quantum mechanics. Studying a specific example, we show that assigning an initial state and a unitary time evolution to a quantum system is generally not sufficient to predict the results of a measurement with certainty.
展开▼
机译：讨论了量子力学中“封闭系统”的概念。为此，我们研究了空间上与“宇宙其余部分” Q相距遥远的量子力学系统P的两个模型。在对P和Q之间的相互作用进行合理假设的情况下，我们证明，如果满足以下条件，则系统P表现为封闭系统： P a Q的初始状态属于一大类状态，包括表现出P与Q纠缠的状态。我们用我们的结果来说明量子力学的非确定性。通过研究一个特定的例子，我们表明将初始状态和单一时间演化分配给量子系统通常不足以肯定地预测测量结果。
展开▼
