Quantum field theory has predicted a measurable effect linked to an attractive force, known as the Casimir effect, which arises between metallic elements distanced from each other by a certain level of separation.
Casimir effect is the name of a force of attractive power that is associated with a derivation of the quantum vacuum .
This measurable essence effect that was anticipated by quantum field theory is also known as the Casimir-Polder force . These names allude to both Hendrik Casimir and Dirk Polder , two physicists who carried out an experiment using parallel plates and managed to detect and demonstrate, around 1948 , the existence of this effect/force that is evident between minimally metal elements. separated from each other.
Knowing what it consists of and what generates the Casimir effect is relevant in the fields of nanotechnology and cosmology , for example. As a result of multiple tests and research, it has been predicted that the Casimir effect can sometimes have repulsive power, although there is still much to learn and discover about it.
Concepts and phenomena that are related to the Casimir effect
When collecting information about the particularities of the Casimir effect, it is noted that there are several concepts and phenomena that are related to it.
Van der Waals forces (as defined in the field of physical chemistry as a type of forces between molecules or atoms ) are linked, specifically, to the Casimir effect in dielectric media . In this regard, it is enriching to highlight that the physicist Evgeny Lifshitz contributed to the area of quantum electrodynamics by calculating, in a macroscopic structure of arbitrary essence made up of dielectrics and metals, the Casimir-Polder force .
It must be kept in mind that the Casimir effect manages to manifest itself as a force between objects, specifically referring to the energy level dependent on the formats and locations of dielectric materials and conductive metals . At this point it should be noted that these cause an alteration in the value of the vacuum that is expected in relation to the energy linked to the quantized electromagnetic field .
Through the Casimir effect , it is also possible, in a simple way, to experimentally demonstrate that, within the framework of quantum field theory , zero point energy exists.
The Casimir effect is studied and applied in different areas since, for example, it indicates that quantum forces exist in the vacuum of space.
Experiments
Throughout history , different Casimir effect experiments have been carried out. One of the first to address this topic experimentally was Marcus Spaarnay , who worked with parallel plates and achieved results that, although they did not contradict the theory proposed by Casimir , presented serious errors in the development of the test.
Decades later, Steve K. Lamoreaux took up the matter with Anushree Roy , achieving greater measurement precision. In that case, a flat plate was used and another linked to a sphere with a pronounced radius of curvature . A few years ago, meanwhile, experts from an Italian university used microresonators to determine the Casimir force existing between a pair of plates. Analyzes also emerged focused on the possibility of arriving at a Casimir effect of a repulsive order, but to date this question is still being studied.
Closer in time, research attempts aimed at Casimir's forces of a repulsive nature were recorded. For this, graphene sheets were arranged framed in a high intensity magnetic field . In that context, a quantum Hall effect was observed in graphene and the Landau levels gave discrete energy results.
Nor can we ignore the power attributed to the Casimir effect with respect to its influence on the lateral movement of a sphere that does not maintain contact with any type of surface. This scenario came to light in an attempt to find out what impact the Casimir effect has on the tiniest particles of all. For those responsible for this study, these findings may be important for the development of nanoparticles for the manufacture of technological products or for biomedical research .
The Casimir force has been studied through research based on the use of graphene sheets, to describe a specific case.
Casimir effect varieties
Two great varieties of the Casimir effect are recognized in practice: one dynamic and another that is described as static .
The first classification assumes a mechanism of spontaneous emergence of particles based on the quantum vacuum . When the Casimir effect is presented as dynamic, we notice a production of a series of real photons starting from virtual photons typical of the quantum vacuum .
The static Casimir effect , on the other hand, was appreciated since tests were carried out using a pair of flat mirrors that were located parallel and close to each other. As was proven in that experience, there was an attraction between these elements resulting from virtual particles . It was explained, in this context, that when the gap between the materials is smaller than the wavelength associated with the virtual particles , they are eliminated from said space. Since there is more vacuum pressure inside the hole than outside, then there is enough force to push the mirrors .