A quantum dot is a quantum system in classical space with unique characteristics, as a result of a large quantum limitation. The experimental results of this chapter substantiate the ability of quantum dots to play a key role in purely quantum processes, for example, teleportation of quantum objects, and the generation of macroscopic quantum gravity force and, of course, are a qubit in quantum computing. A quantum dot has the ability to capture (capture) a photo-induced charge carrier by a surface defect of its crystal structure and, thereby, create a second stable long-lived quantum state, which is a necessary requirement for a qubit. This ability puts a quantum dot out of competition with respect to many other quantum objects, like qubits, in terms of the simplicity and cheapness of their continuous generation in standard laboratory conditions. Quantum dots have received wide recognition because of their unique exciton luminescence characteristics; this chapter substantiates a fundamentally new area to use quantum dots in the development and study of both fundamental and applied physics.
- quantum dots
- metastable excitons
- quantum entanglement
Semiconductor quantum dots (QDs), for example, CdSe/ZnS is an attractive quantum object in classical space. Attractiveness is based on the unique characteristics of nanoscale structures with a large quantum limitation. The high quantum yield of exciton luminescence (up to 80%), the narrow band of this luminescence, the long photo stability and the rearrangement of the exciton luminescence band in a wide spectrum range, depending on the size of the nanoparticles, have specific unique characteristics of these crystalline nanostructures . These characteristics provide potential applications in photovoltaic and laser devices, thin-film transistors, light-emitting diodes and luminescent labels in biology and medicine [2, 3, 4, 5, 6]. In this article, I want to justify no less, but rather more, meaningful applications, both in fundamental and in applied physics.
We are talking about the properties of crystalline structures to have on their surface quantum defects called surface trap states. These surface traps capture photo-induced charge carriers, usually an electron, and delay its recombination for a fairly long time [7, 8, 9]. In , the exciton luminescence of CdSe/ZnS QDs was recorded in the millisecond time range and its intensity was six orders of magnitude less than the intensity of exciton luminescence immediately after the photo excitation pulse. Such a quantum state with a long existence of an exciton is called a metastable exciton. A metastable exciton is an electron—hole pair, in which an electron is captured by a surface trap with a long lifetime .
The typical relaxation time of exciton luminescence is the nanosecond time range. Consequently, relaxation of all excited quantum states of QDs takes place in the nanosecond range, whereas relaxation of metastable excitons takes place in the millisecond range, which is six orders of magnitude greater than the lifetime of all other quantum states of QDs. In other words, QDs with a metastable exciton are a quasistable quantum state, and can play the role of a second stable state of QDs, as a qubit. The first stable state of such a qubit is QD in the ground quantum state. The irradiation of a colloid QDs is a simple and practically free way to continuously generate an array of qubits in two stable quantum states, naturally, when the energy of the optical beam quanta exceeds the QD bandgap.
Obviously, we must receive the result of any quantum process, for example, quantum computing or teleportation in the classical space, in the space where we all function. For example, a digital computer operates in its “digital space.” We will need it only when it “produces” a result that is understandable to us, for example, a graph or a picture, but not as a set of numbers. QDs with a metastable exciton, as a qubits in the quantum state , have unique nonlinear optical characteristics. The fact is that the electron capture by the surface trap separates the charge carriers by a distance that coincides with the size of the QD, which are several nanometers. Such a large separation of charge carriers is the source of a very large light-induced dipole moment
We see that quantum dots can be in two stable quantum states, which allows them to be used as a qubit in all modern quantum technologies. One of these quantum states has a significantly different classical refractive index. This property makes it possible to register individual QDs in this quantum state by interferometry methods and, thus, to register the results of quantum processes in classical space. The experimental results of this chapter substantiate and realize this possibility, which opens up new areas for the use of quantum dots in fundamental and applied physics.
2. Teleportation of CdSe/ZnS QDs in the classical space
2.1 Quantum entanglement
Quantum entanglement is a new resource of quantum physics, the same as, for example, energy . New resources make it possible to discover new potentials and implement fundamentally new processes of quantum physics. The modern representation of quantum states is based on the statement that, in quantum mechanics, any physical system is described completely by a state vector in the Hilbert space
A real qubit is a quantum object that has two stable quantum states, which, as a rule, have different easily measured classical characteristics. For example, a quantum of light in the “
As an example, a type of state is usually given
The term “entanglement” was introduced by Schrödinger for the first time in 1935 . Schrödinger introduced this term to describe the specific relationship between quantum systems, which have correlations between their dynamic quantities: position and momentum. And this relationship is expressed in an infinite set of dynamic values of two particles. Thus, Schrödinger justified one of the key properties of quantum entanglement—the complete uncertainty of the values of classical dynamic quantities such as the position and momentum of a particle. And what do we see in Eq. (2)? Here, the quantum state of a quantum superposition of one object in two basic states is written, and decoherence of which will give an equiprobable (1/2) result to find this object, both in the state and in the state . Where is the uncertainty here? Complete uncertainty reflects the form of writing a quantum state |
Thus, we conclude that the quantum state |
2.2 Experimental implementation of multi-particle quantum superposition
Obviously, practical applications make sense with an array of entangled quantum states, the source of which is quantum superposition. Qbits are quantum objects in two basic states, the dynamic characteristics of which, for example, their location, can be easily measured in classical space. It is these qubits, more precisely, their quantum states |0〉 and |1〉 that form the quantum state of many-particle quantum superposition |
The semiconductor quantum dots (QDs) of CdSe/ZnS were used in this work as such qubits. The modern concept of quantum entanglement asserts that quantum entanglement is a consequence of some nonlocality of quantum mechanics, which cannot be explained from the standpoint of classical physics . This concept is the basis for research on quantum communications, quantum cryptography and quantum networks. Let us leave the question of nonlocality “for later,” and let’s discuss the obvious property of quantum entanglement, which is it’s decoherence. An array of tossed and rotating coins will fall to the ground. Each coin will fall on one of its sides. This particular side of the coin is the result of the interaction of all the coins, both among themselves and with external and internal forces, as they rotate. Decoherence of quantum superposition unravels all entangled quantum states into concrete quantum states |0〉 and |1〉 of each qubit in classical space and, thus, makes it possible to record the result of the interaction of forces in quantum superposition or quantum entanglement.
The dynamic principle of quantum superposition states that the quantum state of quantum superposition can occur again after decoherence, if conditions for this exist. Therefore, the continuous functioning of the states of quantum superposition according to the scheme “self-assembly of quantum superposition—decoherence under the influence of external and internal forces—self-assembly of quantum superposition again—decoherence again, etc.” can occur only with continuous generation of the qubit. The quantum state of the qubit |0〉 is the ground unexcited state, which does not require external influence for its existence. The quantum state of the qubit |1〉 is a QD with a metastable exciton. Therefore, the continuous generation of this state is a necessary condition for the continuous functioning of the quantum state of quantum superposition. An optical beam with quantum energy greater than the bandgap is the driving force that is able to generate the state |1〉 continuously.
An optical beam with a wavelength of
2.3 Experimental implementation of teleporting CT CdSe/ZnS
All the experimental results were obtained in a simple experiment, the scheme of which is shown in Figure 1a. This graphic also shows a typical beam trace profile pattern on a remote screen. Figure 1b shows a typical transformation of the pattern of the beam trace profile after the start of illumination. Here, the time of 0 ms is the beginning of the illumination of the QDs suspension, and the intensity distribution is the input beam profile without a cuvette with a suspension with QDs in the beam. The input beam parameters were: beam convergence angle
Quantum teleportation is the concept of quantum physics, which is being studied in a large number of recent published works. The main research topics are quantum communication, quantum computing and quantum networks. The term teleportation means the process by which bodies and objects are transferred from one place to another without moving along any path. The “quantum teleportation” boom begins with article , in which an unknown quantum state is first measured and then reconstructed at a remote place. The implementation of this information protocol requires a classical communication channel , and quantum entanglement . The conceptual basis of such a quantum teleportation is the assertion that two quantum particles in an entangled state have some non-locality so that changes in the state of one particle immediately correlate with changes in the remote system regardless of the signal passing time between them . If this concept is accepted as a physical reality, then one should assume the existence of some otherworldly forces, which, and only they, provide such a speculative correlation between remote quantum objects. This article substantiates another concept of quantum teleportation, which is really a physical reality, since this concept is the result of an experiment.
The meaning of the experiment was to look the transformation of the pattern of the beam trace profile when moving the cuvette with the QDs colloid on a rough surface, as a result of which, the QDs colloid was subjected to micro-shaking. Figure 2 contains information about how the dimensions of the pattern of the beam trace profile change in the process of establishing a steady state and after the beginning of the movement of the cuvette with the colloid QDs. These data were obtained at the position of the cuvette along the axis
It is obvious that the establishment of a stationary state takes place as a result of at least two processes. The first ~400 ms there is an increase in all sizes of the pattern of the beam trace profile. Then, we see a dramatic change in the size behavior of this pattern. An obvious reduction in all sizes of this pattern is observed. We should note that the increase and subsequent reduction in the size of the pattern is well extrapolated by exponential functions. Moreover, the pattern of the upper half of the beam trace profile is reduced to a much greater degree and significantly sooner. We will analyze these experimental results below. Here, we will consider the situation after the beginning of the movement of the cuvette with the colloid to another location along the
The beginning of this movement took place after 3 seconds of continuous illumination. Obviously, the steady state was achieved during this time (see Figure 2). This movement caused a complete “whistleblower” or “orgy” of the dimensions of the beam trace profile pattern, which Figures 2 and 3 demonstrate quite well. We must note that the pattern of the profile of a beam trace changes its structure in an abrupt manner. Details of the pattern of each frame in Figure 3 do not coincide with the details of the pattern of the previous frame of the video. All patterns of each frame change their details “jump.” Recall that the time between frames was 40 ms. Here we should especially note that all the processes that controlled the size of the pattern immediately before the beginning of the displacement had characteristic relaxation times of 200–300 ms, which significantly exceeded the actual time of a cardinal change of the pattern itself.
Another key result is that the axis of the output optical beam coincides with the axis of the input optical beam with all the “manipulations” with the cuvette with a colloid: its movement along the
The pattern of the beam trace profile changes its structure and dimensions “abruptly” in each frame of the video. Figure 4 shows how the digital profile of the beam trace profile pattern changes its structure and size after the beginning of the displacement (0 ms) of the cuvette along the z axis and after 120 ms. Here we have to remind that the beginning of movement took place after 3 seconds of continuous illumination, when the pattern of the beam trace profile was in a steady state with a characteristic exponential relaxation time
Figures 2–4 contain information that shows that the micro shake of a QDs colloid transforms the pattern of the beam trace profile over a time that is significantly shorter than the characteristic exponential relaxation time of the steady state of the QDs colloid. Here we recall that the pattern of the beam trace profile is a pattern of wave aberrations of the wave surface of the light-induced refractive index volume [17, 18]. The photoinduced refractive index of a colloid of QDs results from the accumulation of the concentration of QDs with a light-induced metastable exciton . Consequently, the transformation of the pattern of the beam trace profile is the result of the transformation of the distribution of the concentration of QDs with a metastable exciton in the illuminated volume of the QDs suspension. Figure 4 convincingly shows that a substantial concentration of QDs with a metastable exciton, providing phase addition to the wave front of the input beam, for example, at 14
In principle, this behavior of the QDs concentration is expected. Micro-shaking is a source of forces that can cause flows in a liquid, which mix the concentration of QDs. But, the fact is that micro-shock causes forces with an arbitrary direction. It is obvious that such forces should cause arbitrary concentration flows in a liquid, which should cause an arbitrary geometric displacement of the optical beam, its axis, in the first place. The experiment shows that arbitrary QDs concentration fluxes with a metastable exciton really arise, but all these fluxes “spin” around the axis of the input optical beam. The axis of the input beam has “unshakable” directions and retains its direction for all mechanical perturbations of the cell with QDs colloid. This means only one thing: there are no real flows of QDs concentration in the liquid, and what we see is the result of teleportation of the quantum states of a metastable exciton. Quantum teleportation “transfers” only quantum states from one quantum object to another quantum object. The trajectory of the transfer, of course, is absent. We have implemented a unique situation where mechanical classical forces are small enough to cause a real disturbance of the fluid, but these forces easily cause quantum teleportation, which does not have a trajectory of movement in classical space. The lack of a trajectory of movement clearly means that there is no actual movement of objects in space. Obviously, there is no movement; therefore, there are no forces that prevent this movement. This means that what we see is the result of the direct action of the forces not “burdened” by the opposition of any other forces.
The fundamental and practical significance, as well as novelty, of these results cannot be overestimated. The fundamental significance and novelty lies in the fact that the resource of entangled quantum states creates a macroscopic wave function regardless of temperature. Quantum teleportation transports quantum states of neutral particles, for example, quantum dots with a metastable exciton, without a specific trajectory of motion in classical space. Since there is no movement trajectory, then there is no movement itself. Movement is not, means that there are no forces that impede movement. There are no such force, which means that there is no internal friction. There is no internal friction in a fluid, for example, in a colloid of quantum dots, and there is a real displacement of a quantum dot, since a quantum state with a metastable exciton is another stable quantum state of quantum dots in classical space, and therefore it is another quantum object. Moving quantum objects in a liquid without internal friction is the basis for the implementation of a superfluid quantum liquid, regardless of temperature. Superconductivity can be realized regardless of the temperature on the same quantum entanglement resource, but for this it is necessary to confuse the quantum states of charged qubits.
Practical significance and novelty lies in the fact that quantum teleportation allows you to register super-weak forces. Obviously, a super-weak force can impart to a super-small mass a sufficiently large acceleration, which is easy to register, especially in the absence of internal friction. On this basis, the possibility of developing super sensitive sensors, for example, for registration of gravitational waves, but in the size of an ordinary laboratory table opens.
To conclude this section, we formulate the physics of the quantum teleportation process of entangled quantum states. The obvious condition of quantum teleportation is that entangled quantum states must occupy a macroscopic volume. It is the volume in which the geometric displacement of quantum states takes place. In this work, this volume determines the geometry of the input optical beam, as well as, for example, in . This optical beam light induces a second stable quantum state (QD with a metastable exciton) from the first state (QD in the ground quantum state), in other words, the optical beam generates classical two-level qubits, which at a sufficiently high concentration self-organize into a quantum state of quantum superposition with 2
3. Quantum gravity as macroscopic force
Quantum gravity is a well-established term in the framework of the creation of the unified field theory, and this term means a quantum description of gravitational interaction. Obviously, the process of describing the gravitational interaction is not related to the emergence of gravitational force, as a fundamental force that plays a key role in nature. I propose to return quantum gravity to its original meaning as the primary source of interaction forces in nature. Quantum mechanics and general relativity are two fundamental theories that underlie the theory of quantum gravity. But, these theories are based on supposedly different a conceptual principle, which does not allow creating a unified field theory based on the theory of quantum gravity. Direct experiments in the field of quantum gravity are inaccessible to modern technologies due to the weakness of gravitational interactions. This is only a short list of difficulties that arise when trying to understand what quantum gravity is. I propose to combine the supposedly different conceptual principles of quantum mechanics and the general theory of relativity not to create a theory of Kant’s gravity, but for the experimental realization of quantum gravity as a macroscopic force.
Obviously, any quantum object has mass. Then, the gravitational interaction between these objects, as bodies having a certain mass, is called quantum gravity by analogy with the classical concept of gravity. The mass of quantum objects is very small, and then it is obvious that the force of such quantum gravity, due to mass, can play a significant role and be detected at very small distances. It is believed that this distance determines the absolute unit of Planck’s length, which is 10−33 cm. Penetration into the scale of units of length and Planck’s time requires the creation of a density of 1099 cm−3 objects. For this you need to build a collider size, probably from the Milky Way. These are supposedly obvious direct experiments, the technology of which cannot be realized at the present time.
I propose another technology for creating quantum gravity as a macroscopic force precisely on the basis of the conceptual compatibility of quantum mechanics with the general theory of relativity. For this, I propose to assume that quantum gravity, as a force, is the result of the space-time curvature of the field from the point of view of the general theory of relativity. And from the point of view of quantum mechanics, the source of quantum gravity should bend the space-time field at the quantum level. The moving mass creates a curvature of the space-time field in classical space; therefore it is the source of classical gravity. Then, by analogy, quantum gravity should arise as a result of a quantum process that bends the space-time field at the quantum level. Such a process exists and is generally known. This process is the transition of any quantum object from one quantum state to another quantum state, since the wave function of any quantum state transforms itself in space and time, and therefore bends space-time, with any change of quantum states. This is a well-known and generally accepted experimental fact. It is obvious that the curvature of the space-time field and, therefore, quantum gravity, as a force, will increase with an increase in the number of such quantum transitions. I propose to consider a quantum state called quantum superposition as a kind of quantum space that contains 2
3.1 The results of the experiment and discussion
The experimental results of part 2 of this article substantiate the teleportation of quantum dots with a metastable exciton under the action of external classical forces. This teleportation is the result of quantum teleportation of the “metastable exciton” quantum state. This result looks like a fantasy, but this result is a physical reality, since the qubit is a quantum object in two stable basic states. This means that a qubit in the state (QD in the ground state) and a qubit in the state (QD with a metastable exciton) are different quantum objects in the classical space. Figure 1b shows the transformation of the pattern of the beam trace profile in the process of achieving a steady state. A nonlinear optical response is formed as a result of a photoinduced change in the refractive index. QDs with metastable excitons are the direct source of this photoinduced refractive index. Therefore, the stationary state of the nonlinear response is established when the concentration of quantum dots with a metastable exciton is established in the stationary state. And this is due to the accumulation of quantum dots with a metastable exciton, as a state with a long relaxation time. Therefore, the unique flattening of the upper half of the beam profile pattern should be associated with the accumulation of QDs in the state. The experimental results of Figure 5 confirm this statement and show how the beam trace profile “comes” to its stationary state when the colloid was in the position
The fact is that the authors of almost all works consider that if the optical medium absorbs optical radiation, then the nonlinear optical response is thermal nonlinearity. Thermal nonlinearity is a consequence of a decrease in the density of the optical medium as a result of its heating. The non-linear thermal lens is, as a rule, negative and it defocuses the optical beam. The defocusing of the optical beam manifests itself as an increase in the size of the beam trace profile on a remote screen.
Figure 5 shows, with all the evidence, that the size of the beam trace profile coincides with the size of the input beam trace profile during the entire time of establishment of the steady state. This means that there is no thermal nonlinear lens, and a unique transformation of the output beam profile pattern is present. Therefore, the flattening of the beam trace pattern is a result of the action of forces that increase with the accumulation of QDs with a metastable exciton.
The obvious direction of action of these forces is shown in Figure 6, which shows the transformation of the pattern of the beam trace profile in the position of a cell with a colloid near the waist of the input optical beam. The input beam has a maximum intensity, and it illuminates the minimum volume of the nonlinear medium in this position. Therefore, the curvature of the wave front of the light-induced lens increases in comparison with the curvature at positions far from the waist of the input beam. The optical power of this lens also increases. The size and number of rings of the beam trace profile pattern increases, and the time to steady state is reduced. The files videos 1–3.gif demonstrates the transformation of the beam trace profile for this position of a colloid cell in real time. Collapse (self-focusing) of the optical beam takes place at the very beginning of illumination of a nonlinear medium. A typical Townes profile  is formed in the first 40 ms after the start of illumination. A dozen rings are formed already to 120 ms after the start of illumination. The increase in the number of rings and the simultaneous “lowering” of the whole pattern of the beam trace profile downward is observed in the time interval 160–600 ms after the start of illumination. Subsequently, the upper half of the beam trace continues to descend, forming only three contrasting rings that do not “go” beyond the horizon, as at
The photos in Figure 7 demonstrate the pattern of the beam trace profile when the colloid shines through in the vertical “bottom-up” direction. It can be seen that the beam trace profile remains axisymmetric all the time. Transformation of different parts of the beam trace profile is absent.
Obviously, the horizontal scanning of the colloid differs from the vertical in that the gravitational force of the Earth is directed perpendicular to the beam axis, whereas with vertical scanning the gravity force is parallel to the beam axis. In other words, we are in a situation where two mechanical forces have different directions. One force is terrestrial gravity, and it is directed vertically downwards, and the other force is light-induced force and it is directed to the axis of the optical beam. Then, the resultant force is the sum of two forces in the upper half of the beam trace profile, and there is the difference of these forces in the lower half of the beam trace profile. As a result, the upper half of the beam profile is compressed almost completely, and the lower half of the profile is compressed slightly.
Section 2.2 of this paper justifies the property of QDs to form quantum superposition with 2
The practical significance of such a force of quantum gravity solves the long-term problem of thermonuclear fusion of nuclei. The modern concept of nuclear synthesis suggests that plasma temperatures of 108–109 K will provide automatic synthesis of nuclei with a positive energy output. This concept is based on experimental results that are obtained repeatedly on particle accelerators. The real synthesis of nuclei in the
In conclusion, the concept of quantum gravity was proposed for the first time as a force that arises as a result of the space-time field curvature at the quantum level when a quantum object passes from one state to another quantum state. The concept of real quantum space was first proposed as a quantum state of a multi-particle quantum superposition of
Multi-level semiconductor quantum dots were first proposed as light-induced
The experimental results show that two light-induced fundamental processes manifest themselves in the QDs suspension, which were revealed due to a significant change in the lighting conditions of the QDs suspension (
The result is fundamentally new; we can say there is a revolutionary one, not only for quantum physics, but also for the entire world view, from cosmology to the functioning of all life. Naturally, this result does not coincide with the modern concept of the development of quantum physics, especially if we take into account the complete absence of the mathematical apparatus for quantum space, therefore, the result is fundamentally new. The experimental results shown in this article, for example, quantum teleportation based on the formation of a macroscopic wave function, justify fantastic possibilities to realize the Bose-Einstein condensate regardless of temperature.