Photographic reproduction of oil painting portrait of Samuel Meyer Ehrenberg Portraits Men

Original painting with Louis Rosenzweig, New Haven, CT

Studio portrait of Samuel Isaac Bürger.

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Benjamin Rothschild and Herbert Samuel

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"... I want an Ocean between us!" : Letters from Samuel Kahn, devoted father of one of the thousand children brought from Germany to the United States in 1934.

The manuscript contains letters written by Samuel Kahn to his daughter in the USA between 1934 and 1937.

Portrait of Samuel Mayer Ehrenberg ( 1773 - 1853 ).

This painting is in dedication " in honor of Meyer Ehrenberg by his students" as stated on a scroll held by the sitter. The scroll is dated October 7, 1820 and is followed by a list of names in two columns: (M.Ehrenberg, P.Ehrenberg, B. Ehrenberg, M.Imanuel M.Balke, B.Meier, L.Franck, M. Cohen, W.Fraenkel, M. Chohns, P.Goldschmidt, J.Lippoa, A. Nathan, M.Kramer, J.Fraenkel, M.Goldschmidt.) Ehrenberg was the founder of the first modern Jewish Day School in Germany, at Wolfenbuettel. Ehrenberg was the great-grandfather of the Jewish Theologian Franz Rosenzweig.

Letter from Moses Levy regarding New York congregation's agreement to pay half cost for return of Reverend H. H. Samuel Cohen

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Double time window targeting technique: Real-time DMRG dynamics in the Pariser-Parr-Pople model

We present a generalized adaptive time-dependent density matrix renormalization-group (DMRG) scheme, called the double time window targeting (DTWT) technique, which gives accurate results with nominal computational resources, within reasonable computational time. This procedure originates from the amalgamation of the features of pace keeping DMRG algorithm, first proposed by Luo et al. [Phys. Rev. Lett. 91, 049701 (2003)] and the time-step targeting algorithm by Feiguin and White [Phys. Rev. B 72, 020404 (2005)]. Using the DTWT technique, we study the phenomena of spin-charge separation in conjugated polymers (materials for molecular electronics an spintronics), which have long-range electron-electron interactions and belong to the class of strongly correlated low-dimensional many-body systems. The issue of real-time dynamics within the Pariser-Parr-Pople (PPP) model which includes long-range electron correlations has not been addressed in the literature so far. The present study on PPP chains has revealed that, (i) long-range electron correlations enable both the charge and spin degree of freedom of the electron, to propagate faster in the PPP model compared to Hubbard model, (ii) for standard parameters of the PPP model as applied to conjugated polymers, the charge velocity is almost twice that of the spin velocity, and (iii) the simplistic interpretation of long-range correlations by merely renormalizing the U value of the Hubbard model fails to explain the dynamics of doped holes/electrons in the PPP model.

The Proto-Lucianic Problem in 1 Samuel

The Lucianic text of the Septuagint of the Historical Books witnessed primarily by the manuscript group L (19, 82, 93, 108, and 127) consists of at least two strata: the recensional elements, which date back to about 300 C.E., and the substratum under these recensional elements, the proto-Lucianic text. Some distinctive readings in L seem to be supported by witnesses that antedate the supposed time of the recension. These witnesses include the biblical quotations of Josephus, Hippolytus, Irenaeus, Tertullian, and Cyprian, and the Old Latin translation of the Septuagint. It has also been posited that some Lucianic readings might go back to Hebrew readings that are not found in the Masoretic text but appear in the Qumran biblical texts. This phenomenon constitutes the proto-Lucianic problem. In chapter 1 the proto-Lucianic problem and its research history are introduced. Josephus references to 1 Samuel are analyzed in chapter 2. His agreements with L are few and are mostly only apparent or, at best, coincidental. In chapters 3 6 the quotations by four early Church Fathers are analyzed. Hippolytus Septuagint text is extremely hard to establish since his quotations from 1 Samuel have only been preserved in Armenian and Georgian translations. Most of the suggested agreements between Hippolytus and L are only apparent or coincidental. Irenaeus is the most trustworthy textual witness of the four early Church Fathers. His quotations from 1 Samuel agree with L several times against codex Vaticanus (B) and all or most of the other witnesses in preserving the original text. Tertullian and Cyprian agree with L in attesting some Hebraizing approximations that do not seem to be of Hexaplaric origin. The question is more likely of early Hebraizing readings of the same tradition as the kaige recension. In chapter 7 it is noted that Origen, although a pre-Lucianic Father, does not qualify as a proto-Lucianic witness. General observations about the Old Latin witnesses as well as an analysis of the manuscript La115 are given in chapter 8. In chapter 9 the theory of the proto-Lucianic recension is discussed. In order to demonstrate the existence of the proto-Lucianic recension one should find instances of indisputable agreement between the Qumran biblical manuscripts and L in readings that are secondary in Greek. No such case can be found in the Qumran material in 1 Samuel. In the text-historical conclusions (chapter 10) it is noted that of all the suggested proto-Lucianic agreements in 1 Samuel (about 75 plus 70 in La115) more than half are only apparent or, at best, coincidental. Of the indisputable agreements, however, 26 are agreements in the original reading. In about 20 instances the agreement is in a secondary reading. These agreements are early variants; mostly minor changes that happen all the time in the course of transmission. Four of the agreements, however, are in a pre-Hexaplaric Hebraizing approximation that has found its way independently into the pre-Lucianic witnesses and the Lucianic recension. The study aims at demonstrating the value of the Lucianic text as a textual witness: under the recensional layer(s) there is an ancient text that preserves very old, even original readings which have not been preserved in B and most of the other witnesses. The study also confirms the value of the early Church Fathers as textual witnesses.

A density matrix renormalization group study of low-lying excitations of polythiophene within a Pariser-Parr-Pople model

Symmetrized density-matrix-renormalization-group calculations have been carried out, within Pariser-Parr-Pople Hamiltonian, to explore the nature of the ground and low-lying excited states of long polythiophene oligomers. We have exploited C-2 symmetry and spin parity of the system to obtain excited states of experimental interest, and studied the lowest dipole allowed excited state and lowest dipole forbidden two photon state, for different oligomer sizes. In the long system limit, the dipole allowed excited state always lies below the lowest dipole forbidden two-photon state which implies, by Kasha rule, that polythiophene fluoresces strongly. The lowest triplet state lies below two-photon state as usual in conjugated polymers. We have doped the system with a hole and an electron and obtained the charge excitation gap and the binding energy of the 1(1)B(u)(-) exciton. We have calculated the charge density of the ground, one-photon and two-photon states for the longer system size of 10 thiophene rings to characterize these states. We have studied bond order in these states to get an idea about the equilibrium excited state geometry of the system. We have also studied the charge density distribution of the singly and doubly doped polarons for longer system size, and observe that polythiophenes do not support bipolarons.

Band to correlated crossover in alternating Hubbard and Pariser-Parr-Pople chains: Nature of the lowest singlet excitation of conjugated polymers

The evolution with increasing Coulomb correlations of a semiconductor to a magnetic insulator is related to an excited-state crossover in pi-electron models for conjugated polymers. We associate strong fluorescence with a lowest singlet excitation S1 that is dipole allowed, on the band side, while S1 becomes two-photon allowed on the correlated side. S1/S2 crossovers in Hubbard, Pariser-Parr-Pople, or other chains with electron-hole symmetry and alternating transfer integral t(1 +/- delta) are based on exact results at delta=0 and 1, on molecular exciton theory at large delta, and on oligomer calculations up to twelve sites.

Exact eigenstates of the Pariser-Parr-Pople model for anthracene

The pi-electronic structure of anthracene is discussed by combining exact solutions of the Pariser-Parr-Pople (PPP) model and semiempirical PM3 calculations. Symmetry adaptation of the 2.8 million singlet valence-bond (VB) diagrams is explicitly demonstrated for D2h and electron-hole symmetry. Standard PPP parameters provide a comprehensive fit to one- and two-photon anthracene spectra and intensities up to the strong 1 B-1(3u)-absorption at 5.24 eV, the 10th excited state in the dense correlated spectrum, and indicate a reassignment of two-photon absorptions. The singlet-triplet gap and fine-structure constants also agree with experiment. Fully-relaxed PM3 geometries are obtained for the anthracene ground state and for singlet, triplet, and charged bipolarons. The PM3 bond lengths correlate well with PPP bond orders for the idealized structure. Single-determinantal PM3 excitation and relaxation energies for bipolarons are consistent with exact PPP results and contrast all-valence electron with pi-electron calculations. Several correlation effects are noted in the rich pi-spectra of anthracene in connection with improved PPP modeling of conjugated molecules and polymers.

Density-matrix renormalization-group study of low-lying excitations of polyacene within a Pariser-Parr-Pople model

We have carried out symmetrized density-matrix renormalization-group calculations to study the nature of excited states of long polyacene oligomers within a Pariser-Parr-Pople Hamiltonian. We have used the C-2 symmetry, the electron-hole symmetry, and the spin parity of the system in our calculations. We find that there is a crossover in the lowest dipole forbidden two-photon state and the lowest dipole allowed excited state with size of the oligomer. In the long system limit, the two-photon state lies below the lowest dipole allowed excited state. The triplet state lies well below the two-photon state and energetically does not correspond to its description as being made up of two triplets. These results are in agreement with the general trends in linear conjugated polymers. However, unlike in linear polyenes wherein the two-photon state is a localized excitation, we find that in polyacenes, the two-photon excitation is spread out over the system. We have doped the systems with a hole and an electron and have calculated the charge excitation gap. Using the charge gap and the optical gap, we estimate the binding energy of the 1(1)B(-) exciton to be 2.09 eV. We have also studied doubly doped polyacenes and find that the bipolaron in these systems, to be composed of two separated polarons, as indicated by the calculated charge-density profile and charge-charge correlation function. We have studied bond orders in various states in order to get an idea of the excited state geometry of the system. We find that the ground state, the triplet state, the dipole allowed state, and the polaron excitations correspond to lengthening of the rung bonds in the interior of the oligomer while the two-photon excitation corresponds to the rung bond lengths having two maxima in the system.

Effect of dimerization on dynamics of spin-charge separation in Pariser-Parr-Pople model: A time-dependent density matrix renormalization group study

We investigate the effect of static electron-phonon coupling on real-time dynamics of spin and charge transport in pi-conjugated polyene chains. The polyene chain is modeled by the Pariser-Parr-Pople Hamiltonian with dimerized nearest-neighbor parameter t(0)(1 + delta) for short bonds and t(0)(1 - delta) for long bonds, and long-range electron-electron interactions. We follow the time evolution of the spin and charge using time-dependent density matrix renormalization group technique when a hole is injected at one end of the chain in its ground state. We find that spin and charge dynamics followed through spin and charge velocities depend both on chain length and extent of dimerization delta. Analysis of the results requires focusing on physical quantities such as average spin and charge polarizations, particularly in the large dimerization limit. In the dimerization range 0.0 <= delta <= 0.15, spin-charge dynamics is found to have a well-defined behavior, with spin-charge separation (measured as the ratio of charge velocity to spin velocity) as well as the total amount of charge and spin transported in a given time along the chain decreasing as dimerization increases. However, in the range 0.3 <= delta <= 0.5, it is observed that the dynamics of spin and charge transport becomes complicated. It is observed that, for large delta values, spin-charge separation is suppressed and the injected hole fails to travel the entire length of the chain.