Energija osnovnog stanja višečestinog fermionskog sistema određena pomoću Feenbergove perturbacione teorije

In this paper we derive an expression for the ground state energy of N identical interacting fermions by using Brillouin-Wigner-Feenberg perturbation theory. It represents a generalization of the Gell-Mann-Brueckner formula which was obtained for dense electron gas.U ovom radu određen je izraz za energiju osnovnog stanja sistema od N identičnih fermiona koji međudjeluju dvočestičnim potencijalom. Izraz je dobiven upotrebom Brillouin-Wigner-Feenbergova računa smetnje. Primijenjen na elektronski plin, izraz predstavlja poopćenje Gell-Mann-Bruecknerove formule za gust elektronski plin. Izvršena je i jedna procjena, korekcija u odnosu na Gell-Mann-Bruecknerov izraz, za tekući 3He. U našem saznanju ovo je prvi rad koji učinkovito opisuje fermionske sisteme koristeći se Feenbergovim računom smetnje

Interakcija među elementarnim pobuđenjima bozonskog fluida u bogoljubovljevoj aproksimaciji

The effective interaction energy of quasiparticles in the Bose fluid, which is described by "ladder state diagrams" in the Bogoliubov approximation, was studied for a model potential. It is shown that in the Bogoliubov approximation, the interaction of excitations in liquid 4He can not be described even qualitatively. It means that a model of the weakly interacting dilute Bose gas fails in describing the interaction between excitation in Bose-condensed liquid, although this model qualitatively incorporates superfluidity in itself.Pokazano je da u Bogoljubovljevoj aproksimaciji interakcija elementarnih pobuđenja u Bozonskim fluidima ne može biti opisana čak ni kvalitativno. U računu je korišten rearanžirani Feenbergov račun smetnje. Ovaj je rezultat neočekivan glede činjenice da opis pojedinačnih elementarnih pobuđenja u modelu ”slabo međudjelujućeg bozonskog plina”, kvalitativno sadrži suprafluidni spektar

Učinci zakašnjelih sila u helijevim diatomskim molekulama

The binding energies of helium-3 dimer, helium-4 dimer and 3He - 4He molecule in the state 1 1S - 1 1S are calculated using the standard variational procedure. It is shown that the binding energy depends on the retardation long-range potentials. The expectation value of the internuclear distance for each complex is also derived.Primjenom standardnog varijacijskog postupka, izračunale su se vezne energije dimera helium-3 i helium-4, te molekule 3He – 4He. Pokazuje se kako vezna energija ovisi o zakašnjenju dugodosežnih potencijala. Izvedene su i očekivane vrijednosti međunukleonskih razmaka za svaki spoj

Učinci zakašnjelih sila u helijevim diatomskim molekulama

The binding energies of helium-3 dimer, helium-4 dimer and 3He - 4He molecule in the state 1 1S - 1 1S are calculated using the standard variational procedure. It is shown that the binding energy depends on the retardation long-range potentials. The expectation value of the internuclear distance for each complex is also derived.Primjenom standardnog varijacijskog postupka, izračunale su se vezne energije dimera helium-3 i helium-4, te molekule 3He – 4He. Pokazuje se kako vezna energija ovisi o zakašnjenju dugodosežnih potencijala. Izvedene su i očekivane vrijednosti međunukleonskih razmaka za svaki spoj

Interakcija među elementarnim pobuđenjima bozonskog fluida u bogoljubovljevoj aproksimaciji

The effective interaction energy of quasiparticles in the Bose fluid, which is described by "ladder state diagrams" in the Bogoliubov approximation, was studied for a model potential. It is shown that in the Bogoliubov approximation, the interaction of excitations in liquid 4He can not be described even qualitatively. It means that a model of the weakly interacting dilute Bose gas fails in describing the interaction between excitation in Bose-condensed liquid, although this model qualitatively incorporates superfluidity in itself.Pokazano je da u Bogoljubovljevoj aproksimaciji interakcija elementarnih pobuđenja u Bozonskim fluidima ne može biti opisana čak ni kvalitativno. U računu je korišten rearanžirani Feenbergov račun smetnje. Ovaj je rezultat neočekivan glede činjenice da opis pojedinačnih elementarnih pobuđenja u modelu ”slabo međudjelujućeg bozonskog plina”, kvalitativno sadrži suprafluidni spektar

Variational Study of Fermionic Helium Dimer and Trimer in Two Dimensions

In variational calculation, we have obtained the binding energy of helium 3 dimer in two dimensions. The existence of one bound State, with the binding energy -0.014 mK, has been definitively found. Also, the existence of a binding state of helium 3 trimer having spin -1/2 with the energy below -0.0057 mK is indicated. This re-opens the question of the existence of the gas phase of many helium 3 atoms on the surface of superfluid helium 4

Some Relations for the Ground State Energy and Helium Diatomic Molecules

It is shown quite generally that the ground state energy of two atoms in infinite space, interacting via a spherical potential that depends only on the distance between particles, is the lowest in two dimensions. Using variational procedure, binding energies of helium diatomic molecules, in infinite and restricted spaces, are obtained as well. The results derived for helium atoms are in accord with the lemma

Thrombopoietin receptor agonist romiplostim in refractory thrombocytopenia as a bridging therapy to the second allogeneic stem cell transplantation

Thrombopoietin (TPO) receptor agonist romiplostim mimic the action of TPO and stimulate the activation, proliferation and maturation of megakaryocytes, resulting in an increase in circulating platelet counts. In this work, we present a patient with a Ph-negative chronic myeloid leukemia (CML) with refractory thrombocytopenia treated with romiplostim as a bridging therapy to the second allogeneic stem cell transplantation (alloSCT). A 56-year old male patient was diagnosed with an atypical Ph-negative CML. One year after the diagnosis he underwent alloSCT from HLA-matched unrelated donor, but had early graft rejection, with severe bleeding diathesis, anemia and thrombocytopenia refractory to transfusion therapy. In addition to daily platelet transfusions (sometimes 2 times per day), he received tranexamic acid and intravenous immunoglobulins. Since the severe thrombocytopenia persisted, romiplostim was introduced as subcutaneous once per week treatment. After two weeks of romiplostim therapy, platelet count increased and the need for platelet transfusions decresed, and he was further followed up in outpatient setting receiving romiplostim as a bridging therapy to his second alloSCT that he received latter. This work describe an unusual use of the TPO receptor agonist as a bridging therapy between two alloSCTs to treat severe refractory thrombocytopenia

Energy States of Helium-4 Dimer

It is shown that the binding energy of helium-4 dimer for the same class of potentials depends on the set of potential parameters used. The existence of one excited vibrational state of the dimer, which is related to one node of the radial wave function, is also proved for all used potentials. Excited state energy is about (–0,3 mK) ⋅ kB. The expectation value of the internuclear distance is about 49 Å in the ground state and 679 Å in the excited state