Igor Smolyaninov leder en grupp forskare i arbetet med att skapa osynlighet med hjälp av en teknisk utrustning som gör det möjligt att flytta infallande ljus från en sida av ett objekt till objektets andra sida på så sätt att det förefaller att ha passerat rakt igenom det mellanliggande objektet. Experimentet har utförst med utgångspunkt från en teori utvecklad av Vladimir Shalaev. Det unika med detta experiment är att det för första gången genomförts med ljus i det för människor synliga ljusspektrumet. Tidigare lyckade experiment har legat utanför spektrumet för synligt ljus.
Optical space in metamaterials may be engineered to mimic the landscape of a multidimensional Universe which has regions of different topology and different effective dimensionality. The “metamaterial landscape” may include regions in which one or two spatial dimensions are compactified. Nonlinear optics of metamaterials in these regions mimics either U(1) or SU(2) Kaluza-Klein theories having one or more kinds of effective charges. As a result, novel “photon blockade” nonlinear optical metamaterial devices may be realized. Topology-changing phase transitions in such metamaterials lead to considerable particle creation perceived as flashes of light, thus providing a toy model of birth of an individual physical Universe.
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| METAMATERIAL MULTIVERSE STRUCTURE |
Fig.1 According to current understanding of the Multiverse, it is populated by vacua of all possible dimensionalities. A spacelike slice through a multi-dimensional Multiverse is shown. The dark regions represent black holes and black branes. This is a “metamaterial” adaptation of picture presented in the same reference.
The newfound freedom of control of the local dielectric permittivity εik and magnetic permeability μik tensors in electromagnetic metamaterials has fueled recent explosion in novel device ideas based on the concept of “electromagnetic space” , which is different from the actual physical space, and may have non-trivial topology. While current emphasis of research in this field is concentrated in the area of novel electromagnetic devices, linear and nonlinear optics of metamaterials may also have far reaching implications for fundamental physics. For example, optics of metamaterials has a unique capability to realize a table top model of the physical Multiverse.
Understanding of our physical world as a tiny fraction of a vast multi-dimensional Multiverse has gained considerable recent attention. String theory, Kaluza-Klein theories, and many other higher-dimensional theories, suggest the existence of a landscape of vacua with diverse topologies and physical properties. The landscape generally includes spaces with different numbers of compactified dimensions shown in Fig.1, with the characteristic size of the compactified dimension being on the order of the Planck length. The symmetries of this compactified internal space define the gauge symmetries and therefore physical laws (types of charges and their interactions) governing a particular region of the Multiverse. Topology-changing transitions between vacua with different numbers of compact dimensions appear to be especially interesting in this model. Such a transition may represent the birth of an individual physical Universe.
Here we demonstrate that using extraordinary waves in anisotropic uniaxial metamaterials, optical models of such space-times as dS3xS1 (3D de Sitter space with one compactified dimension) and dS2xS2 (2D de Sitter space with two compactified dimensions) may be realized. Other non-trivial possibilities, such as the metamaterial models of 4D de Sitter dS4 and anti de Sitter AdS4 spaces are also shown in Fig.1. Nonlinear optics of these metamaterial spaces is shown to resemble interaction of charges via gauge fields.
Together with recent demonstrations of the metamaterial wormholes and black holes which are supposed to connect metamaterial regions having different effective topology, these observations complete the model of the metamaterial Multiverse presented in Fig.1.
Let us start by demonstrating how to produce the dS3xS1 electromagnetic space-time geometry using metamaterials. Spatial geometry of this space-time may be approximated as a product R2xS1 of a 2D plane R2 and a circle S1.
In addition to non-trivial nonlinear optics, the described toy model of the Metamaterial Multiverse lets us study metric phase transitions in which the topology of the “optical space” changes as a function of temperature or an applied field. A similar topological transition may have given birth to our own Universe. According to some theoretical models, during the Inflation our 4D Universe expanded exponentially at the expense of compactification of the extra spatial dimensions. During this process a large number of particles had been created. Metamaterial optics is probably the only other physical system in which a similar process can be observed. Let us consider a topological transition from the R3 metamaterial space to either R2xS1 or R1xS2 topology. The number of photons emitted during such metric topology change can be calculated via the dynamical Casimir effect. The total energy E of emitted photons from a phase changing volume V depends on the photon dispersion laws in the respective phases.
In conclusion, we have demonstrated that optics of metamaterials presents us with new opportunities to engineer topologically non-trivial “optical spaces”. Nonlinear optics of extraordinary light in these spaces resembles Coulomb interaction of effective charges. Therefore, novel “photon blockade” devices may be engineered. Topology-changing phase transitions in such metamaterials resemble birth of a physical Universe.
