verschränken

Verschränken is a German verb meaning to entwine, interlace, or interlock. In everyday language it can describe physically interwoven objects, such as Zweige verschränken (twigs interlacing) or Stoff verschränken (fabric interlacing). In a technical or scientific context the term Verschränkung and its noun form are most commonly associated with quantum physics.

In quantum mechanics, Verschränkung refers to quantum entanglement, a property of a composite system in which the joint state cannot be described as a simple product of the states of its parts. For entangled systems, measurements on one part reveal correlations with the other that cannot be explained by classical local variables. A familiar example is a pair of qubits prepared in a Bell state, where the outcome of measuring one qubit’s property immediately constrains the possible outcomes for the other, regardless of the distance between them. Entanglement is a resource for tasks such as quantum teleportation, quantum key distribution and various quantum computing protocols. It also implies that while correlations can be strong, they do not enable faster-than-light communication since individual measurement results are inherently random.

Historically, the paradoxes associated with entanglement were highlighted in the 1935 Einstein–Podolsky–Rinen (EPR) paper, and Schrödinger coined the term Verschränkung. Experimental tests of Bell inequalities by Alain Aspect in the 1980s and subsequent loophole-free experiments in the 2010s provided strong empirical support for quantum entanglement.

Beyond physics, the verb remains common for describing any interwoven or entangled arrangement, while in science “Verschränkung” designates a nonclassical correlation with profound foundational and practical implications.