{"id":90429,"date":"2023-08-04T17:58:17","date_gmt":"2023-08-04T17:58:17","guid":{"rendered":"https:\/\/www.techopedia.com\/?post_type=definition&p=90429"},"modified":"2023-08-04T18:03:47","modified_gmt":"2023-08-04T18:03:47","slug":"quantum-tunneling","status":"publish","type":"definition","link":"https:\/\/www.techopedia.com\/definition\/quantum-tunneling","title":{"rendered":"Quantum Tunneling"},"content":{"rendered":"
Quantum tunneling is a distinctively quantum mechanical phenomenon that sounds straight out of a sci-fi narrative. It defies classical physics’ expectations as it involves particles ‘tunneling’<\/a> through energy barriers that, theoretically, they should not have the energy to surmount.<\/p>\n For example, imagine an electron approaching an energy barrier. In classical physics, if the electron lacks the requisite energy to overcome the barrier, it would be reflected back.<\/p>\n However, in the quantum realm, there’s a probability that this electron can appear on the other side of the barrier as if it passed right through \u2013 hence the term “tunneling.”<\/p>\n This peculiarity arises because particles in quantum mechanics can behave like waves<\/a>, and these waves do not stop at the barrier but instead slowly decrease in amplitude, allowing for the potential for the particle to exist beyond the barrier.<\/p>\n Describing the process of quantum tunneling involves delving into the abstract concepts of quantum mechanics.<\/p>\n Unlike classical particles, quantum particles are described by a wave function, which provides probabilities of where the particle may be found.<\/p>\n When such a quantum particle encounters a barrier, its wave function doesn\u2019t abruptly end at the barrier’s edge; it decreases exponentially, extending into and beyond the barrier.<\/p>\n This means there’s a non-zero probability of finding the particle on the other side of the barrier, even if the particle doesn\u2019t technically have enough energy to cross it.<\/p>\n The probability of tunneling happening is influenced by factors such as the width and height of the barrier and the mass of the particle.<\/p>\n Smaller, lighter particles are more likely to tunnel than larger, heavier ones, and a narrower, lower barrier is easier to tunnel through than a wider, higher one.<\/p>\nHow Does Quantum Tunneling Work?<\/span><\/h2>\n
History of Quantum Tunnelling<\/span><\/h2>\n