![]() ![]() On a submicron scale, this force becomes so strong that it becomes the dominant force between uncharged conductors. īecause the strength of the force falls off rapidly with distance, it is measurable only when the distance between the objects is extremely small. Thus it can be interpreted without any reference to the zero-point energy (vacuum energy) of quantum fields. ![]() In fact, "Casimir's original goal was to compute the van der Waals force between polarizable molecules" of the conductive plates. The treatment of boundary conditions in these calculations has led to some controversy. This force has been measured and is a striking example of an effect captured formally by second quantization. Although the Casimir effect can be expressed in terms of virtual particles interacting with the objects, it is best described and more easily calculated in terms of the zero-point energy of a quantized field in the intervening space between the objects. When this field is instead studied using the quantum electrodynamic vacuum, it is seen that the plates do affect the virtual photons which constitute the field, and generate a net force – either an attraction or a repulsion depending on the specific arrangement of the two plates. In a classical description, the lack of an external field means that there is no field between the plates, and no force would be measured between them. The typical example is of two uncharged conductive plates in a vacuum, placed a few nanometers apart. In modern theoretical physics, the Casimir effect plays an important role in the chiral bag model of the nucleon in applied physics it is significant in some aspects of emerging microtechnologies and nanotechnologies. For example, beads on a string as well as plates submerged in turbulent water or gas illustrate the Casimir force. Since the value of this energy depends on the shapes and positions of the materials, the Casimir effect manifests itself as a force between such objects.Īny medium supporting oscillations has an analogue of the Casimir effect. The Casimir effect can be understood by the idea that the presence of macroscopic material interfaces, such as electrical conductors and dielectrics, alter the vacuum expectation value of the energy of the second-quantized electromagnetic field. Lamoreaux quantitatively measured the Casimir force to within 5% of the value predicted by the theory. It was not until 1997 that a direct experiment by Steven K. The fundamental principles leading to the London–van der Waals force, the Casimir force, and the Casimir–Polder force can be formulated on the same footing. ![]() Their result is a generalization of the London– van der Waals force and includes retardation due to the finite speed of light. In the same year, Casimir together with Dirk Polder described a similar effect experienced by a neutral atom in the vicinity of a macroscopic interface, which is called the Casimir–Polder force. It is named after the Dutch physicist Hendrik Casimir, who predicted the effect for electromagnetic systems in 1948. On, or outside the light-cone.In quantum field theory, the Casimir effect (or Casimir force) is a physical force acting on the macroscopic boundaries of a confined space which arises from the quantum fluctuations of a field. In fact, our Figures 3 and 4 in SR:kinematics are maps of 2-dimensional spacetime, namely of the events We shall need it in ourĭevelopment of relativistic mechanics. Great conceptual and practical utility in SR, and, in its generalizedįorm, essential in general relativity. 1.4 Four-velocity and four-acceleration. ![]()
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