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Physics

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2001

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Articles 301 - 330 of 391

Full-Text Articles in Physical Sciences and Mathematics

Chiral Symmetry And The Parity-Violating Nn Pi Yukawa Coupling, Sl Zhu, Sj Puglia, Br Holstein, Mj Ramsey-Musolf Jan 2001

Chiral Symmetry And The Parity-Violating Nn Pi Yukawa Coupling, Sl Zhu, Sj Puglia, Br Holstein, Mj Ramsey-Musolf

Physics Department Faculty Publication Series

We construct the complete SU(2) parity-violating (PV) π,N,Δ interaction Lagrangian with one derivative, and calculate the chiral corrections to the PV Yukawa NNπ coupling constant hπ through O(1/Λχ3) in the leading order of heavy baryon expansion. We discuss the relationship between the renormalized hπ, the measured value of hπ, and the corresponding quantity calculated microscopically from the standard model four-quark PV interaction. We observe that the renormalized hπ depends strongly on a number of a priori unknown parameters in the PV effective Lagrangian.


Intermediate Spin, Schrödinger Cat States, And Nanomagnets, S. E. Barnes Jan 2001

Intermediate Spin, Schrödinger Cat States, And Nanomagnets, S. E. Barnes

Physics Articles and Papers

Quantum tunneling in nanomagnets finds a natural description in terms of intermediate spin. Periodic magnetic effects correspond to a change of flux by the flux quantum Φ0. Schrödinger cat states with different superpositions of the applied magnetic field occur. The molecular magnet Fe8 is discussed and new effects are predicted for Mn12.


Microwave Ionization Of An Atomic Electron Wave Packet, Michael W. Noel, Lung Ko, T. F. Gallagher Jan 2001

Microwave Ionization Of An Atomic Electron Wave Packet, Michael W. Noel, Lung Ko, T. F. Gallagher

Physics Faculty Research and Scholarship

A short microwave pulse is used to ionize a lithium Rydberg wave packet launched from the core at a well-defined phase of the field. We observe a strong dependence on the relative phase between the motion of the wave packet and the oscillations of the field. This phase dependent ionization is also studied as a function of the relative frequency. Our experimental observations are in good qualitative agreement with a one-dimensional classical model of wave packet ionization.


A New Mechanism For Spin-Lattice Relaxation Of Heavy Nuclei In The Solid State: 207pb Relaxation In Lead Nitrate, John B. Grutzner, Kevin W. Stewart, Roderick E. Wasylishen, Michael D. Lumsden, Cecil Dybowski, Peter A. Beckmann Jan 2001

A New Mechanism For Spin-Lattice Relaxation Of Heavy Nuclei In The Solid State: 207pb Relaxation In Lead Nitrate, John B. Grutzner, Kevin W. Stewart, Roderick E. Wasylishen, Michael D. Lumsden, Cecil Dybowski, Peter A. Beckmann

Physics Faculty Research and Scholarship

No abstract provided.


Multilayer Mim Inversion Of Aem Data: Theory And Field Example, Clyde J. Bergeron Jr, Juliette W. Ioup, Yan Wu, George E. Ioup, Kenneth W. Holladay Jan 2001

Multilayer Mim Inversion Of Aem Data: Theory And Field Example, Clyde J. Bergeron Jr, Juliette W. Ioup, Yan Wu, George E. Ioup, Kenneth W. Holladay

Physics Faculty Publications

This paper presents a multilayer generalization of an algebraic method of inverting frequency-doma in airborne active electromagnetic (AEM) data in terms of 1-D layered earth models. The processing of the AEM data, which includes a recalibration procedure, is also outlined. The inversion is applied to synthetic fields generated from a multilayer model which is intended to approximate a measured conductivity profile of the water column in the Gulf of Mexico and to measured AEM data from a survey of the Barataria Bay estuary region of the Louisiana Gulf of Mexico coast. The inversion results from the synthetic data are in …


Energy Localization Invariance Of Tidal Work In General Relativity, Marc Favata Jan 2001

Energy Localization Invariance Of Tidal Work In General Relativity, Marc Favata

Department of Physics and Astronomy Faculty Scholarship and Creative Works

It is well known that when an external general relativistic (electric-type) tidal field (Formula presented) interacts with the evolving quadrupole moment (Formula presented) of an isolated body the tidal field does work on the body (“tidal work”)—i.e., it transfers energy to the body—at a rate given by the same formula as in Newtonian theory: (Formula presented) Thorne has posed the following question: In view of the fact that the gravitational interaction energy (Formula presented) between the tidal field and the body is ambiguous by an amount (Formula presented) is the tidal work also ambiguous by this amount, and therefore is …


Reactivity And Electronic Structure Of Aluminum Clusters: The Aluminum-Nitrogen System, B. D. Leskiw, A. W. Castleman Jr., C. Ashman, S. N. Khanna Jan 2001

Reactivity And Electronic Structure Of Aluminum Clusters: The Aluminum-Nitrogen System, B. D. Leskiw, A. W. Castleman Jr., C. Ashman, S. N. Khanna

Physics Publications

The stability of anionic aluminum–nitrogen clusters has been examined and Al2N−, Al3N−2,Al5N−2, Al6N−3, Al8N−3, and Al9N−2 are found to be particularly stable. Theoreticaldensity functional calculations on neutral and anionic AlnN (n=1–8) clusters were performed and the stability and reaction energetics with oxygen examined. Clusters requiring less than 5.7 eV to remove an electron and an Al atom are shown to be resistant to the reaction with oxygen.


Geometry, Electronic Structure, And Energetics Of Copper-Doped Aluminum Clusters, S. N. Khanna, C. Ashman, B. K. Rao, P. Jena Jan 2001

Geometry, Electronic Structure, And Energetics Of Copper-Doped Aluminum Clusters, S. N. Khanna, C. Ashman, B. K. Rao, P. Jena

Physics Publications

Using density functional theory and generalized gradient approximation for exchange-correlation potential, we have calculated the equilibrium geometries and energetics of neutral and negatively charged AlnCu (n=11,12,13,14) clusters. Unlike the alkali atom-doped aluminum clusters in the same size range, the copper atom resides inside the aluminum cluster cage. Furthermore, the 3d and 4s energy levels of Cu hybridize with the valence electrons of Al causing a redistribution of the molecular orbital energy levels of the Aln clusters. However, this redistribution does not affect the magic numbers of AlnCu clusters that could be derived by assuming that Cu donates one electron to …


Electronic Structure And Chemical Bonding Of 3d-Metal Dimers Scx, X=Sc-Zn, G. L. Gutsev, P. Jena, B. K. Rao, S. N. Khanna Jan 2001

Electronic Structure And Chemical Bonding Of 3d-Metal Dimers Scx, X=Sc-Zn, G. L. Gutsev, P. Jena, B. K. Rao, S. N. Khanna

Physics Publications

The electronic and geometrical structures of the ground and excited states of the homonuclear Sc2, mixed ScTi, ScV, ScCr, ScMn, ScFe, ScCo, ScNi, ScCu, and ScZn 3d-metal dimers and their anions have been calculated using the density functional theory with generalized gradient approximation for the exchange-correlation potential. The ground states of the neutral dimers are found to be 5Σ−u (Sc2), 6Σ+ (ScTi), 7Σ+ (ScV), 4Σ+ (ScCr), 3Σ+ (ScMn), 2Δ(ScFe), 1Σ+ (ScCo), 2Σ+ (ScNi), 3Δ(ScCu), and 4Σ+ (ScZn). A natural bond analysis reveals an antiferrimagnetic spin coupling in the ground states of ScCr, ScMn, and ScFe. This is due to the …


Energetics And Electronic Structure Of Carbon Doped Aluminum Clusters, B. K. Rao, P. Jena Jan 2001

Energetics And Electronic Structure Of Carbon Doped Aluminum Clusters, B. K. Rao, P. Jena

Physics Publications

The energetics and the electronic structure of AlnC clusters (n=3, 4, 5; 11, 12, 13) have been studied by a global optimization of their geometry without any symmetry constraint. The total energies of these clusters both in neutral and charged states are calculated using an all-electron basis and the generalized gradient approximation to the density functional theory. While Al4C and Al12C clusters share some characteristic features of closed shell structures, namely enhanced stability and low electron affinity compared to their neighboring sizes, their ionization potentials exhibit different behavior. These decrease steadily from Al3C to Al5C while that of Al12C is …


Electronic Structure Of Chromium Oxides, Cron- And Cron (N=1-5) From Photoelectron Spectroscopy And Density Functional Theory Calculations, G. L. Gutsev, P. Jena, Hua-Jin Zhai, Lai-Sheng Wang Jan 2001

Electronic Structure Of Chromium Oxides, Cron- And Cron (N=1-5) From Photoelectron Spectroscopy And Density Functional Theory Calculations, G. L. Gutsev, P. Jena, Hua-Jin Zhai, Lai-Sheng Wang

Physics Publications

The electronic structure of CrO−n and CrOn (n=1–5) was investigated using anion photoelectron spectroscopy and density functional theory. Photoelectron spectra of CrO−n were obtained at several photon energies and yielded electron affinities, vibrational and electronic structure information about the neutral CrOn species. Density functional theory calculations were carried out for both the neutrals and anions and were used to interpret the experimental spectra. Several low-lying electronic states of CrO were observed and assigned from photodetachment of the CrO− ground state(6∑+) and an excited state (4∏), which is only 0.1 eV higher. The main spectral features of CrO−2 were interpreted based …


Orientation And Speed Of The Parsec-Scale Jet In Ngc4261 (3c270), B. Glenn Piner, Dayton L. Jones, Ann E. Wehrle Jan 2001

Orientation And Speed Of The Parsec-Scale Jet In Ngc4261 (3c270), B. Glenn Piner, Dayton L. Jones, Ann E. Wehrle

Physics

NGC 4261 (3C 270) is an elliptical galaxy containing a 300 pc–scale nuclear disk of gas and dust imaged by the Hubble Space Telescope (HST), around a central supermassive black hole. Previous VLBI observations of NGC 4261 revealed a gap in emission in the radio counterjet, presumably due to free-free absorption in the inner parsec of the accretion disk. Here we present three 8 GHz VLBA observations of NGC 4261 that allow us to monitor the location and depth of the gap and check for motions in the jet and counterjet. The separation between the brightest peak and …


Coptcr:C Nanocomposite Films For High Density Recording, H. Zeng, M.L. Yan, Yi Liu, David J. Sellmyer Jan 2001

Coptcr:C Nanocomposite Films For High Density Recording, H. Zeng, M.L. Yan, Yi Liu, David J. Sellmyer

David Sellmyer Publications

We report results on the magnetic properties of nanocomposite films of the form (Co86Cr14)xPt1-x:C, which were prepared by magnetron sputtering and subsequent annealing. X-ray diffraction shows that these films consist of CoPtCr grains with the face-centered-tetragonal structure embedded in an amorphous C matrix. Magnetic properties such as coercivity (Hc), remanence ratio (S), and coercive squareness (S*) are strongly dependent on the Pt and C composition and annealing temperatures. Compared with previously reported CoPt:C films with a equiatomic Co and Pt ratio, lower exchange coupling and …


Measurement Of Dσ/Dy For High Mass Drell-Yan E+E- Pairs From Pp̅ Collisions At √S =1.8 Tev, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration Jan 2001

Measurement Of Dσ/Dy For High Mass Drell-Yan E+E- Pairs From Pp̅ Collisions At √S =1.8 Tev, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

No abstract provided.


Two-Center Effect On Low-Energy Electron Emission In Collisions Of 1-Mev/U Bare Ions With Atomic Hydrogen, Molecular Hydrogen, And Helium: Ii. H2 And He, Lokesh C. Tribedi, P. Richard, L. Gulya´S, M. Eugene Rudd Jan 2001

Two-Center Effect On Low-Energy Electron Emission In Collisions Of 1-Mev/U Bare Ions With Atomic Hydrogen, Molecular Hydrogen, And Helium: Ii. H2 And He, Lokesh C. Tribedi, P. Richard, L. Gulya´S, M. Eugene Rudd

M. Eugene Rudd Publications

We have studied the energy and angular distributions of low-energy electron emission in collisions of bare carbon ions of 1-MeV/u energy with He and H2 targets. The double-differential cross sections (DDCS’s) are measured for electrons with energies between 0.5 and 300 eV emitted within an angular range of 15° to 160°. The large forward-backward asymmetry observed in the angular distributions is explained in terms of the two-center effect. Single differential cross sections (SDCS’s) and total cross sections are also derived by integrating the DDCS’s over emission angles and energies. The data are compared with different theoretical calculations based on …


Perspectives Of Giant Magnetoresistance, Evgeny Y. Tsymbal, David G. Pettifor Jan 2001

Perspectives Of Giant Magnetoresistance, Evgeny Y. Tsymbal, David G. Pettifor

Evgeny Tsymbal Publications

Giant magnetoresistance (GMR) is one of the most fascinating discoveries in thin-film magnetism, which combines both tremendous technological potential and deep fundamental physics. Within a decade of GMR being discovered in 1988 commercial devices based on this phenomenon, such as hard-disk read-heads, magnetic field sensors and magnetic memory chips, had become available in the market. These achievements would not have been possible without a detailed understanding of the physics of GMR, which requires a quantum-mechanical insight into the electronic spin-dependent transport in magnetic structures.


The Procedure For Determining And Quality Assurance Program For The Calculation Of Dose Coefficients Using Dcal Software, A. Arndt, John P. Shanahan, C. Gold, R. Brey, T. Gesell, Phillip W. Patton, Mark Rudin, K. Eckerman, V. Rusetski, S. Pagava Jan 2001

The Procedure For Determining And Quality Assurance Program For The Calculation Of Dose Coefficients Using Dcal Software, A. Arndt, John P. Shanahan, C. Gold, R. Brey, T. Gesell, Phillip W. Patton, Mark Rudin, K. Eckerman, V. Rusetski, S. Pagava

Transmutation Sciences Physics (TRP)

The development of a spallation neutron source with a mercury target may lead to the production of rare radionuclides. The dose coefficients for many of these radionuclides have not yet been published. A collaboration of universities and national labs has taken on the task of calculating dose coefficients for the rare radionuclides using the software package: DCAL. The working group developed a procedure for calculating dose coefficients and a quality assurance (QA) program to verify the calculations completed. The first portion of this QA program was to verify that each participating group could independently reproduce the dose coefficients for a …


Experimental Investigation Of Steel Corrosion In Lead Bismuth Eutectic (Lbe): Characterization, Species Identification, And Chemical Reactions, John Farley, Dale L. Perry Jan 2001

Experimental Investigation Of Steel Corrosion In Lead Bismuth Eutectic (Lbe): Characterization, Species Identification, And Chemical Reactions, John Farley, Dale L. Perry

Transmutation Sciences Materials (TRP)

The goal of the present research is to achieve a basic understanding of corrosion of steels by Lead Bismuth Eutectic (LBE). Liquid LBE is under consideration in the transmuter as both a coolant and a target material. There have been studies of LBE, especially by the Russians, but a fundamental understanding and verification of its role in the corrosion of steels is still very 2 incomplete. Post-experiment testing and analysis will be performed on steel samples that have been in intimate contact with LBE. Chemical alterations and resulting chemical species will be measured at the steel surface. Techniques to be …


Photoelectron Spectroscopy And The Dipole Approximation, Oliver Hemmers, Dennis W. Lindle Jan 2001

Photoelectron Spectroscopy And The Dipole Approximation, Oliver Hemmers, Dennis W. Lindle

Environmental Studies Faculty Publications

Over the past three decades, the dipole approximation has facilitated a basic understanding of the photoionization process in atoms and molecules. Advances in gas-phase photoemission experiments using synchrotron radiation have recently highlighted nondipole effects at relatively low photon energies while probing the limits of the dipole approximation. Breakdowns in this approximation are manifested primarily as deviations from dipolar angular distributions of photoelectrons. Detailed new results demonstrate nondipolar angular-distribution effects are easily observable in atomic gases at energies well below 1 keV, and, in molecules, a previously unexpected phenomenon greatly enhances the breakdown of the dipole approximation just above the core-level …


Controlling The Optical Properties Of A Conjugated Co-Polymer Through Variation Of Backbone Isomerism And The Introduction Of Carbon Nanotubes, A. Dalton, J. Coleman, M. In Het Panhuis, B. Mccarthy, A. Drury, W. Blau, J. Nunzi, Hugh Byrne Jan 2001

Controlling The Optical Properties Of A Conjugated Co-Polymer Through Variation Of Backbone Isomerism And The Introduction Of Carbon Nanotubes, A. Dalton, J. Coleman, M. In Het Panhuis, B. Mccarthy, A. Drury, W. Blau, J. Nunzi, Hugh Byrne

Articles

The need to control the formation of weakly emitting species in polymers such as aggregates and excimers, which are normally detrimental to device performance, is illustrated for the example of the polymer poly(m-phenylenevinylene-co-2,5-dioctyloxy-p-phenylenevinylene), using the model compound, 2,5-dioctyloxy-p-distyrylbenzene as a comparison. Two different methods, namely a Homer-Emmons polycondensation in dimethylformamide (DMF) and a Wittig polycondensation in dry toluene, have been used during synthesis resulting in a polymer with a predominantly trans-vinylene backbone and a polymer with a predominantly cis-vinylene backbone, respectively. Photoluminescence and absorption spectroscopy indicate that the polymer forms aggregate species in solution with spectra that are distinctly red-shifted …


Random Values Of The Physical Parameters, Jf Donoghue Jan 2001

Random Values Of The Physical Parameters, Jf Donoghue

Physics Department Faculty Publication Series

I briefly describe two motivations, two mechanisms and two possible tests of the hypothesis that the physical parameters of the ground state of a theory can vary in different rerions of the universe.


Development Of Equilibrium After Preheating, Gary Felder, Lev Kofman Jan 2001

Development Of Equilibrium After Preheating, Gary Felder, Lev Kofman

Physics: Faculty Publications

We present a fully nonlinear study of the development of equilibrium after preheating. Preheating is the exponentially rapid transfer of energy from the nearly homogeneous inflaton field to fluctuations of other fields and/or the inflaton itself. This rapid transfer leaves these fields in a highly nonthermal state with energy concentrated in infrared modes. We have performed lattice simulations of the evolution of interacting scalar fields during and after preheating for a variety of inflationary models. We have formulated a set of generic rules that govern the thermalization process in all of these models. Notably, we see that once one of …


Quantum Confinement Transition In A D-Wave Superconductor, Courtney Lannert, T. Senthil, Matthew P. Fisher Jan 2001

Quantum Confinement Transition In A D-Wave Superconductor, Courtney Lannert, T. Senthil, Matthew P. Fisher

Physics: Faculty Publications

We study the nature of the zero-temperature phase transition between a d-wave superconductor and a Mott insulator in two dimensions. In this "quantum confinement transition", spin and charge are confined to form the electron in the Mott insulator. Within a dual formulation, direct transitions from d-wave superconductors at half-filling to insulators with spin-Peierls (as well as other) order emerge naturally. The possibility of striped superconductors is also discussed within the dual formulation. The transition is described by nodal fermions and bosonic vortices, interacting via a long-ranged statistical interaction modeled by two coupled Chern-Simons gauge fields, and the critical properties of …


Electron Spectral Function In Two-Dimensional Fractionalized Phases, Courtney Lannert, Matthew P.A. Fisher, T. Senthil Jan 2001

Electron Spectral Function In Two-Dimensional Fractionalized Phases, Courtney Lannert, Matthew P.A. Fisher, T. Senthil

Physics: Faculty Publications

We study the electron spectral function of various zero-temperature spin-charge separated phases in two dimensions. In these phases, the electron is not a fundamental excitation of the system, but rather “decays” into a spin-1/2 chargeless fermion (the spinon) and a spinless charge e boson (the chargon). Using low-energy effective theories for the spinons (d-wave pairing plus possible Néel order) and the chargons (condensed or quantum-disordered bosons), we explore three phases of possible relevance to the cuprate superconductors: (1) (formula presented) a fractionalized antiferromagnet where the spinons are paired into a state with long-ranged Néel order and the chargons are 1/2-filled …


Investigation Of Magnetopause Reconnection Models Using Two Colocated, Low‐Altitude Satellites: A Unifying Reconnection Geometry, A. Boudouridis, Harlan E. Spence, T. G. Onsager Jan 2001

Investigation Of Magnetopause Reconnection Models Using Two Colocated, Low‐Altitude Satellites: A Unifying Reconnection Geometry, A. Boudouridis, Harlan E. Spence, T. G. Onsager

Physics & Astronomy

Ion precipitation data from two co-orbiting Defense Meteorological Satellite Program satellites (F6 and F8) are used to investigate magnetopause reconnection models. We examine differential fluxes between 30 eV and 30 keV, from a Southern Hemisphere, prenoon pass during the morning of January 10, 1990. Data from the first satellite to pass through the region (F6) show two distinct ion energy dispersions •-1 ø of latitude apart, between 76 ø and 79 ø magnetic latitude. The electron data exhibit similar features at around the same region but with no or little energy dispersion, consistent with their high velocities. We suggest that …


Tracking Of Moving Objects In Scenery Using Subspace Projection Using Independent Component Analysis, Brian J. Noe, Fredric M. Ham Jan 2001

Tracking Of Moving Objects In Scenery Using Subspace Projection Using Independent Component Analysis, Brian J. Noe, Fredric M. Ham

Aerospace, Physics, and Space Science Faculty Publications

A system is developed for tracking moving objects though natural scenery. A technique is presented for performing change detection on imagery to determine the difference between two images or a sequence of images. Form there an algorithm is presented to detect the presence of a new object and/or the deletion of objects. Then the application of a Variable Structure Interacting Multiple Model tracking filter is presented. The method of performing change detection is based upon the concept of image subspace projection. A set of basis image maps are formed when combined with a mixing matrix can recreate the original image. …


Comparing Classical And Quantum Dynamics Of Strong-Field Double Ionization, R. Panfili, J. H. Eberly, Stanley L. Haan Jan 2001

Comparing Classical And Quantum Dynamics Of Strong-Field Double Ionization, R. Panfili, J. H. Eberly, Stanley L. Haan

University Faculty Publications and Creative Works

We compare quantum mechanical and fully classical treatments of electron dynamics accompanying strong field double ionization. The major features seen in quantum mechanical simulations, including the double-ionization jets, are reproduced when using a classical ensemble of two-particle trajectories.


Above‐Threshold Ionization As A Probe Of Multielectron Physics, L. D. Van Woerkom, M. J. Nando, M. A. Walker, G. D. Gillen, H. G. Muller Jan 2001

Above‐Threshold Ionization As A Probe Of Multielectron Physics, L. D. Van Woerkom, M. J. Nando, M. A. Walker, G. D. Gillen, H. G. Muller

Physics

The study of above-threshold ionization (ATI) is now over 20 years old and much has been learned about the interaction of a single atomic electron with intense laser fields. The development of stable, high repetition rate ultrashort pulse laser systems has allowed experiments to probe intricate details of the ionization process using photoelectron and photoion spectroscopies. To date the overwhelming majority of data show that intense laser fields interact with only a single electron at a time to produce the well known features in electron kinetic energy spectra. We will present an overview of state-of-the-art experiments in ATI and show …


Heating And Ionization Of The Intergalactic Medium By An Early X-Ray Background, Aparna Venkatesan, Mark L. Giroux, J Shull Jan 2001

Heating And Ionization Of The Intergalactic Medium By An Early X-Ray Background, Aparna Venkatesan, Mark L. Giroux, J Shull

Physics and Astronomy

Observational studies indicate that the intergalactic medium (IGM) is highly ionized up to redshifts just over 6. A number of models have been developed to describe the process of reionization and the effects of the ionizing photons from the first luminous objects. In this paper we study the impact of an X-ray background, such as high-energy photons from early quasars, on the temperature and ionization of the IGM prior to reionization, before the fully ionized bubbles associated with individual sources have overlapped. X-rays have large mean free paths relative to EUV photons, and their photoelectrons can have significant effects on …


Laser Stabilization At 1536 Nm Using Regenerative Spectral Hole Burning, P B. Sellin, N M. Strickland, Thomas Böttger, J L. Carlsten, R L. Cone Jan 2001

Laser Stabilization At 1536 Nm Using Regenerative Spectral Hole Burning, P B. Sellin, N M. Strickland, Thomas Böttger, J L. Carlsten, R L. Cone

Physics and Astronomy

Laser frequency stabilization giving a 500-Hz Allan deviation for a 2-ms integration time with drift reduced to 7 kHz/min over several minutes was achieved at 1536 nm in the optical communication band. A continuously regenerated spectral hole in the inhomogeneously broadened 4I15/2(1)!4I13/2(1) optical absorption of an Er31:Y2SiO5 crystal was used as the short-term frequency reference, while a variation on the locking technique allowed simultaneous use of the inhomogeneously broadened absorption line as a long-term reference. The reported frequency stability was achieved without vibration isolation. Spectral hole burning frequency stabilization provides ideal laser sources for high-resolution spectroscopy, real-time optical signal processing, …