scholarly journals Unzipping of two random heteropolymers: Ground-state energy and finite-size effects

2008 ◽  
Vol 78 (1) ◽  
Author(s):  
M. V. Tamm ◽  
S. K. Nechaev
Keyword(s):  
Ground State Energy ◽  
Ground State ◽  
Size Effects ◽  
State Energy ◽  
Finite Size ◽  
Finite Size Effects

scholarly journals FINITE SIZE EFFECTS IN ENTANGLED RINGS OF QUBITS

2004 ◽  
Vol 02 (02) ◽  
pp. 149-169 ◽  
Author(s):  
T. MEYER ◽  
U. V. POULSEN ◽  
K. ECKERT ◽  
M. LEWENSTEIN ◽  
D. BRUß
Keyword(s):  
Ground State ◽  
Size Effects ◽  
State Energy ◽  
Nearest Neighbor ◽  
Finite Size ◽  
Nearest Neighbors ◽  
Spin Model ◽  
Total Spin ◽  
Finite Size Effects ◽  
Invariant Rings

We study translationally invariant rings of qubits with a finite number of sites N, and determine the maximal nearest-neighbor entanglement for a fixed z-component of the total spin. For small numbers of sites we present analytical results. We establish a relation between the maximal nearest-neighbor concurrence and the ground state energy of an XXZ spin model. This connection allows us to calculate the concurrence numerically for N≤24. We point out some interesting finite-size effects. Finally, we generalize our results beyond nearest neighbors.

scholarly journals Homogeneous one-dimensional Bose–Einstein condensate in the Bogoliubov’s regime

2016 ◽  
Vol 30 (22) ◽  
pp. 1650307 ◽  
Author(s):  
Elías Castellanos
Keyword(s):  
Ground State ◽  
Size Effects ◽  
Finite Size ◽  
Einstein Condensate ◽  
Finite Size Effects ◽  
One Dimensional ◽  
Bose Einstein Condensate ◽  
Ground State Properties ◽  
Low Dimensional ◽  
Bose Einstein

We analyze the corrections caused by finite size effects upon the ground state properties of a homogeneous one-dimensional (1D) Bose–Einstein condensate. We assume from the very beginning that the Bogoliubov’s formalism is valid and consequently, we show that in order to obtain a well-defined ground state properties, finite size effects of the system must be taken into account. Indeed, the formalism described in the present paper allows to recover the usual properties related to the ground state of a homogeneous 1D Bose–Einstein condensate but corrected by finite size effects of the system. Finally, this scenario allows us to analyze the sensitivity of the system when the Bogoliubov’s regime is valid and when finite size effects are present. These facts open the possibility to apply these ideas to more realistic scenarios, e.g. low-dimensional trapped Bose–Einstein condensates.

Finite-size effects in exponential random graphs

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
A Gorsky ◽  
O Valba
Keyword(s):  
Random Graphs ◽  
Ground State ◽  
Size Effects ◽  
Chemical Potential ◽  
Network Flows ◽  
Finite Size ◽  
Critical Value ◽  
Star Model ◽  
Finite Size Effects ◽  
Exponential Random Graphs

Abstract In this article, we show numerically the strong finite-size effects in exponential random graphs. Particularly, for the two-star model above the critical value of the chemical potential for triplets a ground state is a star-like graph with the finite set of hubs at network density $p<0.5$ or as the single cluster at $p>0.5$. We find that there exists the critical value of number of nodes $N^{*}(p)$ when the ground state undergoes clear-cut crossover. At $N>N^{*}(p),$ the network flows via a cluster evaporation to the state involving the small star in the Erdős–Rényi environment. The similar evaporation of the cluster takes place at $N>N^{*}(p)$ in the Strauss model. We suggest that the entropic trap mechanism is relevant for microscopic mechanism behind the crossover regime.

scholarly journals The energy correction due to a finite size nucleus of the hydrogen atom confined in a penetrable spherical cavity

2018 ◽  
Vol 64 (4) ◽  
pp. 399
Author(s):  
Norberto Aquino ◽  
Alejandro Rojas ◽  
Henry Montgomery Jr.
Keyword(s):  
Hydrogen Atom ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Finite Size ◽  
Point Particle ◽  
Energy Correction ◽  
A Value ◽  
Free Hydrogen ◽  
Uniform Charge Distribution

We computed accurate values for the ground state energy of a hydrogen atom by a finite spherical barrier of height V0 as a function of the confinement radius . We consider the nucleus as a sphere with a uniform charge distribution instead of as a point particle. The contribution to the ground state energy due to the finite nuclear size is computed as a function of the confinement radius,  and the height of the barrier, V0, using time-independent perturbation theory. For an impenetrable cavity with .5 au, we found that this energy correction is fifty times higher than the corresponding value for the free hydrogen atom. For a finite value of V0,we found that the maximum of the energy correction is reached at a value  which very is close to the position at which the electron density is most compact around to the nucleus. This is confirmed though the Shannon entropy in configuration space.

GROUND-STATE ENERGY OF THE SPIN-1/2 TWO-DIMENSIONAL ANTIFERROMAGNETIC HEISENBERG MODEL

1989 ◽  
Vol 03 (09) ◽  
pp. 1443-1446 ◽  
Author(s):  
C.Y. PAN
Keyword(s):  
Ground State Energy ◽  
Ground State ◽  
Heisenberg Model ◽  
State Energy ◽  
Finite Size ◽  
Group Method ◽  
Two Dimensional ◽  
Real Space Renormalization Group ◽  
Antiferromagnetic Heisenberg Model ◽  
Good Agreement

The ground-state energy of the spin-1/2 two-dimensional antiferromagnetic Heisenberg model is obtained by a real space renormalization group method. A relative larger cluster (5×5) is used to improve the accuracy and a boundary theory is applied to extrapolate to the result which is in good agreement with the finite-size calculation and in fairly good agreement with the other available numerical estimates. How to further improve the calculation is discussed.

The ground state energy of the ±J spin glass from the genetic algorithm

1994 ◽  
Vol 4 (9) ◽  
pp. 1281-1285 ◽  
Author(s):  
P. Sutton ◽  
D. L. Hunter ◽  
N. Jan
Keyword(s):  
Genetic Algorithm ◽  
Spin Glass ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy

POLARON IN A QUANTUM DOT UNDER AN ELECTRIC FIELD

2007 ◽  
Vol 21 (24) ◽  
pp. 1635-1642
Author(s):  
MIAN LIU ◽  
WENDONG MA ◽  
ZIJUN LI
Keyword(s):  
Quantum Dot ◽  
Electric Field ◽  
Field Intensity ◽  
Ground State Energy ◽  
Ground State ◽  
Electric Field Intensity ◽  
State Energy ◽  
Theoretical Study ◽  
The Moment ◽  
Transformation Methods

We conducted a theoretical study on the properties of a polaron with electron-LO phonon strong-coupling in a cylindrical quantum dot under an electric field using linear combination operator and unitary transformation methods. The changing relations between the ground state energy of the polaron in the quantum dot and the electric field intensity, restricted intensity, and cylindrical height were derived. The numerical results show that the polar of the quantum dot is enlarged with increasing restricted intensity and decreasing cylindrical height, and with cylindrical height at 0 ~ 5 nm , the polar of the quantum dot is strongest. The ground state energy decreases with increasing electric field intensity, and at the moment of just adding electric field, quantum polarization is strongest.

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