Quantum mechanics and electrodynamics require the presence of fundamental quantum fluctuations of physical currents, cross sections, and process rates. The present paper calculates these fluctuations, shows that they have a simple universal 1/f spectrum, and shows how they invariably come to the foreground in high-technology applications, because in them all other fluctuations and sources of instability have been either eliminated, or otherwise discounted and put under control.>
Quantum mechanics and electrodynamics require the presence of fundamental quantum fluctuations of physical currents, cross sections, and process rates. The present paper calculates these fluctuations, shows that they have a simple universal 1/f spectrum, and shows how they invariably come to the foreground in high-technology applications, because in them all other fluctuations and sources of instability have been either eliminated, or otherwise discounted and put under control.>
The conventional Quantum 1/f (Q1/f) Effect is present in any scattering cross section or process rate involving charged particles or current carriers. The present paper shows how bremsstrahlung and decoherence at all frequencies yield macroscopic quantum interference, resulting in probability density fluctuations at all frequencies in the outgoing scattered beam, that are observed as fundamental base-band 1/f noise and as 1/f frequency fluctuations, or phase noise close to carrier, in materials, devices, and resonant or non-resonant systems. We emphasize the role of the phenomenon of quantum decoherence showing that the fundamental, universal 1/f noise is both a phenomenon of decoherence and of the infrared divergence of quantum electrodynamics. This eliminates the last persisting misunderstandings of the Q1/f Theory and of this new field of Infra-quantum Physics. On this basis we give the first universal engineering formulas, applicable for the ultra-low noise optimization of all Hi-Tech applications, of the materials, devices and systems of modern industry, microelectronics, nanotechnology, highest stability resonators, oscillators and clocks, MEMS, and any resonant and non-resonant sensors. Q1/f noise, i.e, the coherent and conventional Q1/f Effects, is a new fundamental aspect of quantum physics, as basic as space and time. In resonators and oscillators, fundamental frequency fluctuations come usually from 1/f fluctuations in the dissipation.
The quantum 1/f effect is a fundamental new aspect of quantum mechanics, quantum electrodynamics, and quantum field theory in general, with practical importance in most high-technology applications. It is based on the reaction of material currents to their spontaneous emission of infra-quanta such as photons, gravitons, transversal phonons, spin waves, etc. It is the result of decoherence of entangled states of particles and their spontaneous bremsstrahlung, a consequence of infrared-divergent interactions between particles and their field. It is the quantum manifestation of classical turbulence and it represents the most fundamental form of quantum chaos. It is described by the simple universal formula of conventional and coherent quantum 1/f noise, important in engineering, science and technology. It provides a new physical meaning to the notion of “constant current,” in time and space, similar to the 1937 definition of elastic processes by Bloch and Nordsieck. Finally, it is an interesting aspect of the concrete way in which matter generates its forms of existence, for instance time and space. Quantum 1/f spin decoherence rates, known to severely limit the performance of quantum computers, are shown here to be also affected by the quantum 1/f effect. Indeed, the elementary spin-flip process has a bremsstrahlung amplitude, leading to a non-stationary state with 1/f quantum fluctuations, and a disentangled system of non-localized low-frequency photons with negative conditional entropy. Thus, decoherence is due to the entangled system’s interaction with the rest of the world, as is its quantum 1/f fluctuation which can be expressed in qubits. Increasing the spin-excess n is one way to reduce these fluctuations. In general, we find that both decoherence and its quantum 1/f noise could be controlled by better insulating the system in a new way.
Most sensors traduce various environmental, industrial, or laboratory parameters into electrical signals. Quantum sensing pushes this to the ultimate limit of achievable sensitivity, detectivity, resolution, and stability. Quantum mechanics sets these limits through the uncertainty principle. It causes the ubiquitous 1/f noise, as we show here for LiNbO3. Quantum 1/f theory, known as the quantum theory of the fundamental 1/f noise phenomenon, is a new aspect of quantum mechanics, that governs the nonlinear interaction of particle and field, introducing the new notions of "physical cross sections" (PCS) and "physical process rates" (PPR). These contain the fundamental macroscopic quantum 1/f fluctuations. They yield the usually defined PCS and PPR with infrared radiative corrections, when the expectation value is taken over the low-frequency photon states of negative entropy. The physical charged particle, such as an electron, contains both the bare particle and its electromagnetic field. The latter is in a coherent state, where the phase of the electromagnetic field oscillators is determined. Heisenberg’s uncertainty principle then requires that the energy must be uncertain, leading to nonstationary states describing the particle. The particle’s resulting fractional current fluctuations in large devices always have the spectrum 2α/πf, where α=1/137 is the fine structure constant.
Quantum 1/f noise is the manifestation of the coherent and conventional quantum 1/f effects (Q1/fE). The conventional Q1/fE is a fundamental quantum fluctuation of physical cross sections σ and process rates Γ, caused by the bremsstrahlung (recoil) energy and momentum losses of charged particles, when they are scattered, or accelerated in any way. The closely related coherent Q1/fE is present in any current carried by many particles. It is caused by the energy spread characterizing any coherent state of the electromagnetic field oscillators. According to the Heisenberg's uncertainty principle, because an approximation of the phase or position variable is known, exact knowledge of the energy is precluded. This energy spread results in nonstationary energy values, or fluctuations in the energy of the oscillators. To find the spectral density of these inescapable basic fluctuations, which are known to characterize any quantum state, which is not an energy eigenstate, we use an elementary physical derivation based on Schrödinger's definition of coherent states, which can be supplemented by a rigorous derivation from a well-known quantum-electrodynamical branch-point propagator. The example of a simple harmonic oscillator is also useful for illustrating the uncertainty that arises due to Q 1/f Noise. Clearly illustrating the relation between the uncertainty principle and Q 1/f noise.
Abstract : A key step in the construction of quantum computing technologies is the identification and elimination of unwanted sources of noise and its resulting quantum decoherence. In solid state devices, one important source of noise is the fluctuating electric and magnetic fields that come from the device elements themselves. The ultimate source of these fluctuations is the random electric currents that are strongest in the metallic electrodes and leads. This random motion has both thermal and quantum components, though in most devices presently under investigation, the thermal part dominates. In the past, this important physical effect has generally been modeled by picturing the device using an equivalent RC circuit and applying the Nyquist theorem to this circuit. This approach has limitations, since it depends on global quantities, rather than on the detailed geometry and the local electromagnetic properties of the components. Our aim in this research project was to compute the effect from first principles. We considered the underlying physical law (quantum electrodynamics) governing the devices in question. Given the position- and frequency-dependent dielectric function, the electromagnetic noise spectrum can be calculated, and the decohering effect can be deduced. Semiconducting quantum dot and superconducting flux qubits were investigated.