The density matrix renormalization group method. Application to the PPP model of a cyclic polyene chain

The density matrix renormalization group (DMRG) method introduced by White for the study of strongly interacting electron systems is reviewed; the method is variational and considers a system of localized electrons as the union of two adjacent fragments A, B. A density matrix rho is introduced, whose eigenvectors corresponding to the largest eigenvalues are the most significant, the most probable states of A in the presence of B; these states are retained, while states corresponding to small eigenvalues of rho are neglected. It is conjectured that the decreasing behaviour of the eigenvalues is gaussian. The DMRG method is tested on the Pariser-Parr-Pople Hamiltonian of a cyclic polyene (CH)_N up to N=34. A Hilbert space of dimension 5 x 10^+18 is explored. The ground state energy is 10^-3 eV within the full CI value in the case N=18. The DMRG method compares favourably also with coupled cluster approximations. The unrestricted Hartree-Fock solution (which presents spin density waves) is briefly reviewed, and a comparison is made with the DMRG energy values. Finally, the spin-spin and density-density correlation functions are computed; the results suggest that the antiferromagnetic order of the exact solution does not extend up to large distances but exists locally. No charge density waves are present.Comment: 8 pages, RevTex, 2 figures, to be published in the Journal of Chemical Physic

Entanglement in the classical limit: quantum correlations from classical probabilities

We investigate entanglement for a composite closed system endowed with a scaling property allowing to keep the dynamics invariant while the effective Planck constant hbar_eff of the system is varied. Entanglement increases as hbar_eff goes to 0. Moreover for sufficiently low hbar_eff the evolution of the quantum correlations, encapsulated for example in the quantum discord, can be obtained from the mutual information of the corresponding \emph{classical} system. We show this behavior is due to the local suppression of path interferences in the interaction that generates the entanglement. This behavior should be generic for quantum systems in the classical limit.Comment: 10 pages 3 figure

Kesalahan Dokter Dan Sanksinya

Penelitian ini dilakukan dengan tujuan untuk mengetahui bagaimana kesalahan dokter dan sanksinya dalam melakukan tugas profesinya dan bagaimana pengaturan etika profesi bagi seorang dokter. Dengan menggunakan metode penelitian yuridis normatif disimpulkan: 1. Membuktikan adanya kesalahan/kealpaan dokter dalam melakukan profesi tidak cukup hanya dengan pembuktian secara yuridis, tetapi juga pembuktian secara medis didapat dari keputusan majelis dan tidak hanya dari mendengarkan saksi ahli yang dalam hal ini masih dimungkinkan adanya pendapat pribadi yang didapat dari pengalaman praktek dan disokong oleh faktor keberuntungan. Sanksi yang dikenakan terhadap para dokter yang telah terbukti melakukan kesalahan berupa kelalaian atau kesengajaan dalam melakasanakan profesi, yaitu berupa : Dari segi hukum pidana, dokter hanya dapat dituntut dalam hal pasien menderita cacat permanen atau meninggal dunia. Tindakan yang dikenakan terhadap dokter yang melakukan kesalahan profesi yaitu sebagaimana telah diatur dalam Pasal 359, 360, dan 361 KUHP, hukumannya berupa hukuman penjara, kurungan, membayar denda dan apabila kelalaian dilakukan pada saat melakukan pekerjaan, maka hukumannya ditambah sepertiganya dan dipecat dari pekerjaannya. Dari segi hukum perdata, sebagaimana dalam Pasal 1365 KUHPerdata dimana dokter dapat dituntut untuk membayar ganti rugi dalam hal pasien menderita kerugian. Menurut Pasal 29, 190 dan 194 Undang-Undang No. 36 Tahun 2009 tentang Kesehatan, dapat diberikan sanksi berupa pidana penjara dan denda. 2. Kode Etik Kedokteran Indonesia berlaku bagi Dokter Indonesia yang termasuk di dalamnya Sumpah Dokter, merupakan aturan yang harus dijunjung tinggi, dihayati, dan diamalkan oleh para dokter. Untuk membuktikan kesalahan professional di bidang medis, tentu memerlukan standar profesi medis yang hanya ditentukan oleh kelompok profesi itu sendiri. Kata kunci: Kesalahan, dokter, sanks

Identification of the Beutler-Fano formula in eigenphase shifts and eigentime delays near a resonance

Eigenphase shifts and eigentime delays near a resonance for a system of one discrete state and two continua are shown to be functionals of the Beutler- Fano formulas using appropriate dimensionless energy units and line profile indices. Parameters responsible for the avoided crossing of eigenphase shifts and eigentime delays are identified. Similarly, parameters responsible for the eigentime delays due to a frame change are identified. With the help of new parameters, an analogy with the spin model is pursued for the S matrix and time delay matrix. The time delay matrix is shown to comprise three terms, one due to resonance, one due to a avoided crossing interaction, and one due to a frame change. It is found that the squared sum of time delays due to the avoided crossing interaction and frame change is unity.Comment: 17 pages, 3 figures, RevTe

A Decade of Hard Work and Success, 2010–2020

This article1 is an account of the archives and museum at the Sir James Whitney School for the Deaf (SJW) in Belleville, Ontario, which has a long history dating back to 1870. The deaf community affectionately calls this school “Belleville” in American Sign Language after the city where it is located, and so references to the school in this article are also to “the Belleville school.” It is also important to understand that the Belleville school had different names over the years: The school was first called the Ontario Institution for the Education and Instruction of the Deaf and Dumb (OIDD) from 1870 to 1913, and then the Ontario School for the Deaf (OSD) from 1913 to 1974. The year 2020 marked the school’s sesquicentennial and the 10th anniversary of the archives. A former classroom, room no. 13 holds a historical collection of school materials (e.g., artifacts, photographs, documents, and other valuable items) to ensure their preservation and maintenance. Many of them are culturally sensitive to Deaf History, deaf people in general, and the school alumni. Since the archives’ inception three decades ago, employees and volunteers from the deaf community have enthusiastically assisted in the task. As it is known, the OSD-SJW Archives were started in earnest not long after the OSD-SJW Alumni Association came into existence in 1989. Keith George Charles Dorschner, ’56, an alumnus and residential counselor at the school from 1984 to 2001, conceived both schemes with the support and assistance of his wife, the former Christine Margaret Bennett, ’56. (Keith can be seen in Figure 1.) They publicly encouraged the school and alumni communities to donate any physical materials (e.g., records, uniforms, photos, building plans, letters, and graduation certificates) to build an archival collection about the school. However, financial resources for archival showcases and supplies were limited, and they frequently had to move all holdings from one room to another when the school needed the space

Wartime Emergency and the Education of Deaf Children, 1941–1944

According to historical accounts, three Canadian schools for deaf children temporarily vacated their premises during World War II (1939–1945). Under the British Commonwealth Air Training Plan, the Manitoba School for the Deaf in Winnipeg was the third wireless school site for the Royal Canadian Air Force (RCAF), from February 17, 1941, to December 31, 1944. In Vancouver, British Columbia, the RCAF took over the grounds of Jericho Hill School for the Deaf, which was in proximity to the RCAF Station Jericho Beach, from early 1942 to December 1945. And the Ontario School for the Deaf (OSD) in Belleville was home to the RCAF No. 5 Initial Training School (RCAF #5 ITS) for potential aircrew from August 1, 1941, to July 15, 1944 (Figure 1). (Please note that the Ontario School for the Deaf [OSD] is currently named Sir James Whitney School for the Deaf.

John Barrett McGann, Pioneer in Canadian Deaf Education

This article1 is one of several sesquicentennial projects undertaken by staff of the OSD-SJW Archives to commemorate the 150th anniversary (1870–2020) of the Sir James Whitney School for the Deaf (SJW) in Belleville, Ontario. Initially known as the Ontario Institution for the Education and Instruction of the Deaf and Dumb (OIDD), it opened on Thursday, October 20, 1870. This article includes a condensed history of the life of John Barrett McGann, an Irish-born immigrant to Canada in 1855, and his founding of schools for deaf children in Toronto (1858), Hamilton (1864), and Belleville (1870), taken from a forthcoming book by the first author of this article