Giant Atoms Research Articles

Superatomic orbitals

Buckyballs act just like giant atoms, complete with s, p and d orbitals that are bound to the sphere's hollow centre

Coherence-preserving trap architecture for long-term control of giant Ryberg atoms.

We present a way to trap a single Rydberg atom, make it long-lived, and preserve an internal coherence over time scales reaching into the minute range. We propose to trap using carefully designed electric fields, to inhibit the spontaneous emission in a nonresonant conducting structure, and to maintain the internal coherence through a tailoring of the atomic energies using an external microwave field. We thoroughly identify and account for many causes of imperfection in order to verify at each step the realism of our proposal.

A universe of atoms, an atom in the universe

Introduction: The Fire Within / 1. The Wirbelrohr's Roar / 2. Musical Bottles, Flying Balloons, and Hot Stoves: The Uncommon Physics of Common Things / 3. The Unimaginably Strange Behavior of Free Electrons / 4. Quantum Beats and Giant Atoms / 5. And Yet It Moves: Exotic Atoms and the Invariance of Charge / 6. Reflections on Light / 7. Two Worlds, Large and Small: Earth and Atom / 8. Computers, Coins, and Quanta: Unexpected Outcomes of Random Events / 9. A Universe of Atoms: Symmetry, Unity, Gravity, and the Problem of 'Missing Mass' / 10. Science and Wonder

Superconductors as giant atoms predicted by the theory of hole superconductivity

The theory of hole superconductivity proposes that superconductivity originates in the fundamental electron–hole asymmetry of condensed matter and that it is an ‘undressing’ transition. Here we propose that a natural consequence of this theory is that superconductors behave as giant atoms. The model predicts that the charge distribution in superconductors is inhomogeneous, with higher concentration of negative charge near the surface. Some of this negative charge will spill out, giving rise to a negative electron layer right outside the surface of the superconductor, which should be experimentally detectable. Also superconductors should have a tendency to easily lose negative charge and become positively charged. Macroscopic spin currents are predicted to exist in superconducting bodies, giving rise to electric fields near the surface of multiply connected superconductors that should be experimentally detectable.

The attractions of magnetism for nanoscale data storage

The latter half of the 20th century was marked by a ten–million–fold increase in the engineer9ability to store information magnetically (e.g. computer hard–disk drives). Without this, the computing revolution that the developed world has experienced would not have happened. In this paper, I discuss the technical difficulties that face engineering if it is to continue storing increasingly large amounts of information into the third millennium and show how applications of the emerging fields of nanotechnology and quantum engineering may provide solutions. I offer predictions for the course of development of information–storage technology, including concepts such as the quantized magnetic disk, magnetic RAM chips and new magnetic materials made from artificial giant atoms. The changes that might come about in society as a result of mass information storage are discussed.

And yet it moves: strange systems and subtle questions in physics

Preface. The fire within 1. The unimaginably strange behaviour of free electrons 2. Quantum beats and giant atoms 3. And yet it moves: exotic atoms and the invariance of charge 4. Reflections on light 5. Two worlds, large and small: Earth and atom 6. The Wirbelrohr's roar (...or rather whistle) 7. Science and wonder Selected papers by the author Index.

Metal clusters as giant atoms

M12X-type metal clusters of icosahedral symmetry are discussed in terms of the giant atom concept on the basis of the electronic shell structures in free-electron-like metal clusters. The first-principles calculations for Au12,13, Ag12,13, Al12,13, Au12Cr, and Al12Si clusters have been done by the self-consistent local density functional scheme using the norm-conserving pseudopotential in the linear combination of atomic orbitals method. Electronic shell structures in icosahedral clusters are formed by 6s, 5s and 3p orbitals or peripheral atoms in Au, Ag, and Al clusters, respectively. By doping Cr into Au12 and Si into Al12 clusters M13 clusters are stabilized by about 0.7 eV atom-1 (Au12Cr) and 0.2 eV atom-1 (Al12Si) because of the closed shell formation. Interactions between clusters, cluster and surface, and cluster and metal tip used in the atomic force microscope are discussed based on the Harris functional scheme. Dimers of Au12Cr and Al12Si are weakly bound, and the Au13 cluster on Si(111) has two kinds of binding, but Al13 does not. The repulsive or attractive nature of the force between the cluster and Pt tip is considerably dependent on the cluster-tip distance.

Shell Dependent Chemical Reactivity of Large Sodium Clusters

It has been shown in the past that sodium clusters possess an electronic shell structure characteristic of a nearly spherical, finite Fermi system. For this reason they might be expected to behave like giant atoms. In fact, closed shell clusters are known to have particularly high ionization energies. In this paper, we report variations in the reactivity of Nan for 100 ≤ n ≤ 800 with molecular oxygen. Clusters with completely filled electron shells are found to be relatively unreactive.

Stable (Na19)2 as a giant alkali-metal-atom dimer.

We report that a dimer of clusters, (${\mathrm{Na}}_{19}$${)}_{2}$, is energetically stable and explains the abundance of ${\mathrm{Na}}_{38}$ in sodium-cluster mass spectra. A fusion process of two ${\mathrm{Na}}_{19}$ clusters has been studied on the basis of the jellium-sphere-background model by the local-spin-density-functional method. Calculated binding energies show that the force between two clusters is attractive and that the complete fusion is preceded by the formation of a stable (${\mathrm{Na}}_{19}$${)}_{2}$, whose electronic structure is analogous to an alkali-metal--atom dimer, supporting the concept of ``clusters of giant atoms'' for sodium clusters.

Conversion processes in superheavy and giant atoms

Conversion of bound state electrons and internale +,e −-pair creation in superheavy and giant atoms are investigated. We consider various nuclear transitions of multipolaritiesE0, EL andML (L≧1) in superheavy atoms with Z>109. We are concerned in particular with the pecularities of conversion processes in supercritical systems. Our theoretical studies are confronted with the prominent peak structures observed in positron spectra of very heavy collision systems.