The Problem of Nuclear StructureThe atomic nucleus is a quantum many-body system. Conventional probes (photons,electrons, hadrons) interact electromagnetically or strongly with the nucleus, and nonedirectly measures the mass distribution.2.2 The Problem of Nuclear MassMnucleus = Mquarks + Mkinetic + Mgluons + MQCD vacuum + MEM (2)where Mquarks ∼ 1%, Mkinetic ∼ 30%, Mgluons ∼ 30%.2.3 Proposal: Informational Trigger with Combined ModeAn NV center in combined mode (spin + energy) emitsan informational messagethat travels through the substrate channel and acts as aquantum trigger on the atomic nucleus, activating itsinternal degrees of freedom without the need forenergetic excitation.
The Problem of Nuclear StructureThe atomic nucleus is a quantum many-body system. Conventional probes (photons,electrons, hadrons) interact electromagnetically or strongly with the nucleus, and nonedirectly measures the mass distribution.2.2 The Problem of Nuclear MassMnucleus = Mquarks + Mkinetic + Mgluons + MQCD vacuum + MEM (2)where Mquarks ∼ 1%, Mkinetic ∼ 30%, Mgluons ∼ 30%.2.3 Proposal: Informational Trigger with Combined ModeAn NV center in combined mode (spin + energy) emitsan informational messagethat travels through the substrate channel and acts as aquantum trigger on the atomic nucleus, activating itsinternal degrees of freedom without the need forenergetic excitation.
The conventional description of nuclear structure relies heavily on the nuclear mass density function ρ(r) which captures the distribution of nucleons within the nucleus. Recent theoretical developments suggest that this view is incomplete because it neglects the spatial distribution of quantum informational content that arises from many–body correlations and entanglement among nucleons. In this paper we introduce the Nuclear Information Density Spectrum (NIDS), a formalism that assigns to each point inside a nucleus an information density function I(r). This function quantifies the amount of quantum information encoded at each spatial coordinate and is defined through the von Neumann entropy of reduced density matrices of local subsystems. By integrating I(r) over the nuclear volume we recover the total quantum informational content, while the shape of I(r) reflects the distribution of correlation strength throughout the nucleus. We derive explicit expressions for I(r) in terms of the two–body correlation function g2(r1,r2) and outline a strategy to extract I(r) from high–energy elastic and inelastic scattering experiments. The NIDS formalism provides a new lens to view the internal structure of nuclei, potentially redefining shell closures, deformation, and collective modes. Moreover, it offers a quantitative framework to assess the role of quantum correlations in nuclear binding, with implications for the interpretation of exotic nuclei and the equation of state of dense matter. The proposal that the nucleus contains an intrinsic information density invites fresh experimental investigations that could lead to a Nobel–level paradigm shift in nuclear physics.
If we consider the nucleus as a relativistic composite, then we are able to derive from a many-particle Dirac model a coupling between the center of mass motion and internal nuclear degrees of freedom. This interaction can be rotated out in free space, but has the potential to give rise to new physics when two or more nuclei exchange phonons with a common vibrational mode. The simplest example of such a system is a homonuclear diatomic molecule in a frozen matrix, for which we are able to develop an expression for the second-order phonon–nuclear interaction that can result in a splitting of the nuclear energy levels as a result of excitation transfer between the nuclei. The phonon-nuclear coupling is an E1 interaction, so the low energy 6.237 keV E1 transition in 181Ta is special; this motivates an interest in molecular 181Ta2 as a candidate for a Mössbauer experiment where the splitting might be observable. We also consider excitation transfer in the case of a macroscopic a Ta plate.
The conventional description of the atomic nucleus relies heavily on the spatial distribution of nucleons, expressed by the nuclear density function ρ(r). While ρ(r) captures the average position of nucleons, it neglects the intrinsic quantum correlations that arise from the many-body wave function. In this paper, we introduce the Nuclear Information Density Spectrum (NIDS), a formalism that supplements the conventional density with an information density I(r), defined in terms of the local reduced density matrix and an entropic functional. I(r) quantifies the amount of quantum information and correlation present at each point inside the nucleus. We develop the mathematical foundations of NIDS, derive its properties, and discuss its implications for nuclear structure and scattering processes. By integrating NIDS into the analysis of scattering data, we demonstrate that it provides a more nuanced understanding of nuclear dynamics, potentially opening new avenues for precision tests of nuclear models and a deeper appreciation of the underlying quantum many-body physics.
This work discovers and proves that all the photons/quantum particles have a “Nucleus of mass and charge.” The nucleus is located off-center in the particles. The constructive, destructive and intermediate Interference phenomena decisively discover and prove the presence of only one nucleus of the mass located off-center in a photon, like an atomic nucleus. The mass in the nucleus of a photon develops varying forces to move the photon as a wave. The Wave-Particle Duality is the most significant proof of such a nucleus of mass. The formation of an electromagnetic wave by a photon proves the presence of a charge in the nucleus of the photon. The Quantum Theory, developed about 100 years back, simplified the understanding of matter and energy at the atomic/subatomic levels. However, the Quantum Theory remains incomplete and cannot explain even a single quantum phenomenon. The New Quantum Theory, developed in the year 2012, is based on the similarity of an atomic nucleus as well as the solar system with the Sun as its nucleus of the mass and the charge. The New Quantum Theory explains all the Quantum Phenomena and matches with the Classical Mechanics as well as the Theory of Electromagnetism. The experiments described in this work, using high precision instruments, determine the mass, the charge and the diameter of a photon/quantum particle.
Atomic nuclei are complex, quantum many-body systems whose structure manifests itself through intrinsic quantum states associated with different excitation modes or degrees of freedom.Collective modes (vibration and/or rotation) dominate at low energy (near the ground-state).The associated states are usually employed, within a truncated model space, as a basis in (coherent) coupled channels approaches to low-energy reaction dynamics.However, excluded non-collective states can be essential, and their effects on the open (nuclear) system dynamics are usually treated through complex potentials.Is this a complete description of open system dynamics?Does it include effects of quantum decoherence?Can decoherence be manifested in reaction observables?This paper discusses these issues and the main ideas of a coupled-channels density-matrix approach that makes it possible to quantify the role and importance of quantum decoherence in low-energy nuclear reaction dynamics.Some topical applications are highlighted.
This thesis describes a series of experiments on the control of the optical properties of the nitrogen-vacancy (NV) center in diamond, and on control of the electron and nuclear spin states associated with the NV center. The NV center is a fluorescing atomic defect center in diamond, consisting of a substitutional nitrogen atom adjacent to a vacancy in the diamond carbon lattice. The electron spin of the NV center can be initialized and read out optically, and coherently manipulated with high fidelity even at room temperature. This unique combination of properties has attracted much attention to the NV center in recent years for application in quantum information technologies. The experiments in this work focus on exploiting the intrinsic hybrid nature of the NV center. The NV center forms a hybrid spin register, as its electron spin is always coupled to the nuclear spin of its own nitrogen nucleus, and can furthermore be coupled to additional nuclear carbon-13 spins in the diamond. In addition, the electronic spin state can be mapped onto the state of a photon, in principle allowing long range transmission of quantum information and measurement-based entanglement of distant NV center registers. The long-term goal is to achieve a large scale quantum network where the different constituents each perform the task they are most well suited for: the stable nuclear spins store the quantum information, photons transfer quantum information over long distances, and the fast electron spin interfaces between spin and photon states. For measurement-based entanglement of distant NV centers it is of primary importance to maximize the emission and detection of coherent photons emitted by the NV center. Spontaneous emission can be controlled and enhanced by coupling an emitter to a photonic cavity. Chapters 3, 4, and 5 of this thesis describe experiments aimed at maximizing the coherent photon emission rate of an NV center by coupling the NV center to a photonic crystal cavity. One of the main challenges is to position a single NV center into the nanometer-sized cavity mode. Chapter 3 describes the development of a nanopositioning technique, which allows diamond nanocrystals ~50 nm in size containing single NV centers to be placed at arbitrary locations on a chip, with nanometer precision. By using a sharp etched tungsten tip, individual nanocrystals can be picked up, moved and placed under real-time imaging with an electron microscope. We explicitly demonstrate that the unique optical and spin properties of the NV center are conserved by the nanopositioning process. In chapter 4, we apply the nanopositioning technique to couple single NV centers contained in a diamond nanocrystals to gallium phosphide photonic crystal cavities. These cavities resonate in the visible with high quality factors, and are designed to have the lowest energy mode coincide with the zero-phonon line of the NV center. Efficient coupling is evidenced by a strong enhancement of NV center emission at the cavity wavelength. The high quality factor of a photonic crystal cavity is a result of careful design and fabrication. The introduction of a nanocrystal may therefore be expected to have a detrimental effect on the optical properties of a cavity. In chapter 5 we investigate the effect of a nanocrystal on the optical properties of photonic crystal cavities. Our simulations and measurements show that the effect of a nanocrystal is in fact only minor, a promising result for future work on cavity-QED systems in the solid state and with diamond defect centers in particular. Understanding and mitigating decoherence is a key challenge for quantum science and technology. The main source of decoherence for solid-state spin systems is the uncontrolled spin bath environment. Chapter 6 describes experiments that exploit quantum control of the NV center and recently developed dynamical decoupling techniques to study the properties of the surrounding bath of spins belonging to single substitutional nitrogen atoms. The coherence properties of a single NV center are affected by changes in the state of the bath spins, allowing a single NV center to be used as a probe to detect bath spin resonances and study the quantum dynamics of the spin bath. We use quantum control of the spin bath to extend the dephasing time of the NV center, important for the application of the NV center in DC magnetometry. In chapter 7 we describe the development and implementation of decoherence protected quantum gates for the hybrid spin register formed by the NV center electron spin that is coupled to the nuclear spin of its own nitrogen atom. Electron and nuclear spins evolve and decohere at vastly different rates, making it challenging to use such a hybrid system as a fully functional quantum register. We create a universal set of two-qubit quantum gates by integrating dynamical decoupling techniques into the gate operation. We demonstrate the power of our gate design by implementing for the first time Grover's quantum search algorithm on a solid-state spin register.