🌐EnglishEnglishDeutschEspañolFrançaisItalianoPortuguêsSvenskaTiếng Việtالعربيةفارسیहिन्दी中文日本語EntityQ662636· pop 13· linked from 111 articlesnegative energyconcept in physicsAvailable in 12 languagesEspañol日本語PortuguêsالعربيةCentral KurdishHungarianSlovenianSvenskaTiếng ViệtUkrainianConnectionsquantum field theoryEntityvirtual particleEntityCategoriesEnergy (physics)