arXiv subjects

Wung-Hong Huang

Publications and source records attributed to Wung-Hong Huang.

At least 55 records · Page 3Linked to original sources

arXiv2007

On the Supergravity Description of Wilson Loop in Non-commutative Dipole Field Theory

The Wilson loop in the non-commutative dipole field theory is re-examined within the framework of dual gravity description. In contrast to the previous investigations, we let the dual string be moving along the deformed $S^5$ and find the exact expression of the interquark potential. The potential shows a Coulomb behavior at all distance and does not have a minimum distance between quarks, which exhibits in the static configuration. After comparing the potential of the static and moving configurations we find that while the dual string is static at long distance it will transit to a moving configuration at short distance. We also analyze an electric dipole system and find that it shows a similar transition property. Finally, we mention the unsuitable approximation made in the previous paper [hep-th/0701069] and find that the interquark potential in a gauge theory with a non-constant non-commutativity has a Coulomb behavior at all distance.

hep-th↗

arXiv2007

AdS/CFT Approach to Melvin Field Deformed Wilson Loop

We first apply the transformation of mixing azimuthal and internal coordinate to the 11D M-theory with a stack N M2-branes to find the spacetime of a stack of N D2-branes with Melvin one-form in 10D IIA string theory, after the Kaluza-Klein reduction. Next, we apply the Melvin twist to the spacetime and perform the T duality to obtain the background of a stack of N D3-branes. In the near-horizon limit the background becomes the Melvin field deformed $AdS_5 \times S^5$ with NS-NS B field. In the AdS/CFT correspondence it describes a non-commutative gauge theory with non-constant non-commutativity in the Melvin field deformed spacetime. We study the Wilson loop therein by investigating the classical Nambu-Goto action of the corresponding string configuration and find that, contrast to that in the undeformed spacetime, the string could be localized near the boundary. Our result shows that while the geometry could only modify the Coulomb type potential in IR there presents a minimum distance between the quarks. We argue that the mechanism behind producing a minimum distance is coming from geometry of the Melvin field deformed background and is not coming from the space non-commutativity.

hep-th↗

arXiv2007

Dual String Description of Wilson Loop in Non-commutative Gauge Theory

The Wilson loop in some non-commutative gauge theories is studied by using the dual string description in which the corresponding string is on the curved background with B field. For the theory in which a constant B field is turned on along the brane worldvolume the Wilson loop always shows a Coulomb phase, as studied in the previous literature. We extend the examination to the theory with a non-constant B field, which duals to the gauge theory with non-constant non-commutativity, and re-examine the theory in the presence of a nonzero B field with one leg along the brane worldvolume and other transverse to it, which duals to a non-commutative dipole theory. The expectation value of the Wilson loop is calculated to the lowest order by evaluating the area of the string worldsheet. The results show that, while the non-commutativity could modify the Coulomb type potential in IR it may produce a strong repulsive force between the quark and anti-quark if they are close enough. In particular, we find that there presents a minimum distance between the quarks and that the distance is proportional to the value of the non-commutativity, exhibiting the nature of the non-commutative theory.

hep-th↗

arXiv2007

Comment on ``Quantum Statistical Mechanics of an Ideal Gas with Fractional Exclusion Statistics in Arbitrary Dimension"

It is mentioned that anyon thermodynamic potential $Q(α, N)$ could not be factorized in terms characteristic of the ideal boson $α=0$ and fermion $α=1$ gases by the relation $Q(α, N) = (1-α) Q(0, N_b)+ αQ(1, N_f)$ in which $N=N_f +N_b$, that claimed in Phys. Rev. Lett. 78, 3233 (1997). Our analyses indicate that the thermodynamic quantities of anyon gas may be factorized as $Q(α) = αQ(1) + (1-α) Q(0)$ only in the two-dimension system.

cond-mat.stat-mech↗

arXiv2007

Statistics of Anyon Gas and the Factorizable Property of Thermodynamic Quantities

The statistical distribution function of anyon is used to find the eighth viral coefficient in the high-temperature limit and the equation of state in the low-temperature limit. The perturbative results indicate that the thermodynamic quantities, $Q(α)$, of the free anyon gas may be factorized in the terms characteristic of the ideal Bose ($α=0$) and fermion ($α=1$) gases, i.e., $Q(α) = αQ(1) + (1-α) Q(0)$. It is shown that the factorizable property of the thermodynamic quantities, to all orders, can be established from the property of the equivalence between the anyon statistics and statistics in a system with boson-fermion transmutation, which was found by us in a recent paper (hep-th/0308095; Phys. Rev. E 51 (1995) 3729)

cond-mat.stat-mech↗

arXiv2007

Statistical Interparticle Potential between Two Anyons

The density matrix of a two-anyon system is evaluated and used to investigate the "statistical interparticle potential" following the theory of Uhlenbeck. The main purpose is to see how the statistical potential will depend on the fractional statistical parameter $α$. The result shows that the statistical potential for a two-anyon system with $α\ge {1\over2}$ is always repulsive. For the system with $0<α< {1\over2}$, the potential is repulsive at short distances and becomes attractive at long distances. It remains only in the boson system ($α=0$) that the repulsive potential arising from the exclusion principle can disappear and lead to an attractive potential at all distances.

cond-mat.stat-mech↗

arXiv2007

Thermodynamics of Ideal Boson and Fermion Gases in the Static Taub Universe

Some thermodynamic quantities of nonrelativistic ideal boson and fermion gases in the static Taub universe are derived to first order in a small anisotropy parameter d which measuring the deformation from the spherical Einstein universe. They are used to investigate the problem of how the curvature anisotropy affects the thermodynamic behaviors of an ideal gas. It is found that, when the universe is in the oblate configuration (i.e., d > 0), the effect of curvature anisotropy is to increase the number of the fraction in the Bose-Einstein condensation and to decrease the fermion distribution function at low temperature. When the universe is in the prolate configuration (i.e., d < 0), the effects of curvature anisotropy on the thermodynamic quantities is contrary to that in the oblate configuration. The density matrix of a two particle system is evaluated and it is used to define the "statistical interparticle potential" as an attempt to give a "statistical interpretation" about the found thermodynamic behaviors. It is found that when the universe is in the oblate (prolate) configuration the curvature anisotropy will enhance (reduce) both the "statistic attraction" among the bosons and "statistical repulsion" among the fermions. It is expected that such a behavior will also be shown in the relativistic system.

gr-qc↗

arXiv2006

Giant Magnons under NS-NS and Melvin Fields

The giant magnon is a rotating spiky string configuration which has the same dispersion relation between the energy and angular momentum as that of a spin magnon. In this paper we investigate the effects of the NS-NS and Melvin fields on the giant magnon. We first analyze the energy and angular momenta of the two-spin spiky D-string moving on the $AdS_3\times S^1$ with the NS-NS field. Due to the infinite boundary of the AdS spacetime the D-string solution will extend to infinity and it appears the divergences. After adding the counter terms we obtain the dispersion relation of the corresponding giant magnon. The result shows that there will appear a prefactor before the angular momentum, in addition to some corrections in the sine function. We also see that the spiky profile of a rotating D-string plays an important role in mapping it to a spin magnon. We next investigate the energy and angular momentum of the one-spin spiky fundamental string moving on the $R \times S^2$ with the electric or magnetic Melvin field. The dispersion relation of the corresponding deformed giant magnon is also obtained. We discuss some properties of the correction terms and their relations to the spin chain with deformations.

hep-th↗

arXiv2006

Spin Chain with Magnetic Field and Spinning String in Magnetic Field Background

We analyze the fast-moving string in the magnetic Melvin field background and find that the associated effective Lagrangian of string sigma model describes the spin chain model with external magnetic field. The spin vector in the spin chain has been properly deformed and is living on the deformed two-sphere or deformed two-dimensional hyperboloid, depending on the direction around which the string is spinning. We describe in detail the characters of spin deformation and, in particular, see that this is a general property for a string moving in a class of deformed background.

hep-th↗

arXiv2006

Spinning String and Giant Graviton in Electric/Magnetic Field Deformed $AdS_3 \times S^3 \times T^4$

We apply the transformation of mixing azimuthal and internal coordinate or mixing time and internal coordinate to the 11D M-theory with a stack of M2-branes $\bot$ M2-branes, then, through the mechanism of Kaluza-Klein reduction and a series of the T duality we obtain the corresponding background of a stack of D1-branes $\bot$ D5-branes which, in the near-horizon limit, becomes the magnetic or electric Melvin field deformed $AdS_3 \times S^3 \times T^4$. We find the giant graviton solution in the deformed spacetime and see that the configuration whose angular momentum is within a finite region could has a fixed size and become more stable than the point-like graviton, in contrast to the undeformed giant graviton which only exists when its angular momentum is a specific value and could have arbitrary size. We discuss in detail the properties of how the electric/magnetic Melvin field will affect the size of the giant gravitons. We also adopt an ansatz to find the classical string solutions which are rotating in the deformed $S^3$ with an angular momentum in the rotation plane. The spinning string and giant graviton solutions we obtained show that the external magnetic/electric flux will increase the solution energy. Therefore, from the AdS/CFT point of view, the corrections of the anomalous dimensions of operators in the dual field theory will be positive. Finally, we also see that the spinning string and giant graviton in the near-horizon spacetime of Melvin field deformed D5-branes background have the similar properties as those in the deformed $AdS_3 \times S^3 \times T^4$.

hep-th↗

arXiv2006

Electric/Magnetic Field Deformed Giant Gravitons in Melvin Geometry

The rotating D3-brane in the $AdS_5 \times S^5$ spacetime could be blowed up to the spherical BPS configuration which has the same energy and quantum number of the point-like graviton and is called as a giant graviton. The configuration is stable only if its angular momentum was less than a critical value of $P_c$. In this paper we investigate the properties of the giant graviton in the electric/magnetic Melvin geometries of deformed $AdS_5 \times S^5$ spacetime which was obtained in our previous paper (hep-th/0512117, Phys. Rev. D73 (2006) 026007). We find that in the magnetic Melvin spacetime the giant graviton has lower energy than the point-like graviton. Also, the critical value of the angular momentum is an increasing function of the magnetic field flux $B$. In particular, it is seen that while increasing the angular momentum the radius of giant graviton is initially an increasing function, then, after it reach its maximum value it becomes a decreasing function of the angular momentum. During these regions the giant graviton is still a stable configuration, contrast to that in the undeformed theory. Finally, beyond the critical value of angular momentum the giant graviton has higher energy than the point-like graviton and it eventually becomes unstable. Our analyses show that the electric Melvin field will always render the giant graviton unstable.

hep-th↗

arXiv2006

Semiclassical Strings in Electric and Magnetic Fields Deformed $AdS_5 \times S^5$ Spacetimes

We first apply the transformation of mixing azimuthal and internal coordinate or mixing time and internal coordinate to the 11D M-theory with a stack N M2-branes to find the spacetime of a stack of N D2-branes with magnetic or electric flux in 10 D IIA string theory, after the Kaluza-Klein reduction. We then perform the T duality to the spacetime to find the background of a stack of N D3-branes with magnetic or electric flux. In the near-horizon limit the background becomes the magnetic or electric field deformed $AdS_5 \times S^5$. We adopt an ansatz to find the classical string solution which is rotating in the deformed $S^5$ with three angular momenta in the three rotation planes. The relations between the classical string energy and its angular momenta are found and results show that the external magnetic and electric fluxes will increase the string energy. Therefore, from the AdS/CFT point of view, the corrections of the anomalous dimensions of operators in the dual SYM theory will be positive. We also investigate the small fluctuations in these solutions and discuss the effects of magnetic and electric fields on the stability of these classical rotating string solutions. Finally, we find the possible solutions of string pulsating on the deformed spacetimes and show that the corrections to the anomalous dimensions of operators in the dual SYM theory are non-negative.

hep-th↗

arXiv2005

Multi-spin String Solutions in Magnetic-flux Deformed $AdS_n \times S^m$ Spacetime

We perform the dimensional reduction of the spacetime of a stack of N D3-branes by the ``twist'' identification of a circle to obtain a new Melvin background. In the near-horizon limit the background becomes the magnetic-flux deformed $AdS_5 \times S^4$ or $AdS_4 \times S^5$ spacetime. After analyzing the classical closed string solutions with several angular momenta in different directions of the deformed spacetimes we obtain two string solutions. The first solution describes a circular closed string located at a fixed value of deformed $AdS_5$ radius while rotating simultaneously in two planes in deformed $AdS_5$ with equal spins $S$. The second solution describes a string rotating in deformed $S^5$ with two equal angular momenta $J$ in the two rotation planes. We investigate the small fluctuations therein and show that the magnetic fluxes have inclination to improve the stability of these classical string solutions.

hep-th↗

arXiv2005

Fuzzy BIons in Curved Spacetimes

The non-abelian Dirac-Born-Infeld action is used to construct the D2-brane from multiple D0-branes in the curved spacetimes. After choosing the matrix elements as the coordinates of the D0-branes we obtain a simple formula of the Lagrangian for the system in a class of the curved background. Using the formula we first re-examine the system in the flat spacetime and show that, in addition to the fuzzy tube and fuzzy spike which were found in the previous literature, there is the fuzzy wormhole solution. Next, we apply the formula to the system in the geometry of the NS5-branes background. A solution describing the fuzzy BIon of spike profile is obtained. Our investigations show that the size of the matrices is finite for the fuzzy spike in the curved spacetimes.

hep-th↗

arXiv2005

Anti-de Sitter D-branes in Curved Backgrounds

We investigate the properties of the AdS D1-branes which are the bound states of a curved D1-brane with $n$ fundamental strings (F1) in the $AdS_3$ spacetime, and the AdS D2-branes which are the axially symmetric bound states of a curved D2-brane with $m$ D0-branes and $n$ fundamental strings in the $AdS_3 \times S^3$ spacetime. We see that, while the AdS D1-branes asymptotically approach to the event horizon of the $AdS_3$ spacetime the AdS D2-branes will end on it. As the near horizon geometry of the F1/NS5 becomes the spacetime of $AdS_3 \times S^3 \times T^4$ with NS-NS three form turned on, we furthermore investigate the corresponding AdS D-branes in the NS5-branes and macroscopic F-strings backgrounds, as an attempt to understand the origin of the AdS D-branes. From the found DBI solutions we see that in the F-strings background, both of the AdS D1-branes and AdS D2-branes will asymptotically approach to the position with a finite distance away from the F-strings. However, the AdS D2-branes therein could also end on the F-strings once it carries sufficient D0-branes charges. We also see that there does not exist any stable AdS D-branes in the NS5-branes backgrounds. We present physical arguments to explain these results, which could help us in understanding the intriguing mechanics of the formation of the AdS D-branes.

hep-th↗

arXiv2005

Instability of Tachyon Supertube in Type IIA Godel Spacetime

We study the tachyon supertube probes in a type IIA supergravity background which is a stringy-like Gödel spacetime and contains closed timelike curve. In the case of small value of $f$, which is a parameter of the background, we use the Minahan-Zwiebach tachyon action to obtain a single regular tube solution and argue that the tube is a BPS D2-brane. However, we find that the fluctuation around the tube configuration has a negative-energy mode. This means that the tachyon supertube, despite being a BPS configuration, develops an instability in the pathological spacetime with closed timelike curve which violates the causality.

hep-th↗

arXiv2005

Tubular Solutions in NS5-brane, Dp-brane and Macroscopic Strings Backgrounds

We present our searches for the tubular bound states of a D2-brane with $m$ D0-branes and $n$ fundamental strings in the NS5-brane, Dp-brane or macroscopic strings background by solving the Dirac-Born-Infeld equation. The geometry of tubular configurations we considered are taken to be parallel to the background branes or macroscopic strings. The $n$ fundamental strings therein may be the circular strings $F_c$ or the straight strings $F_s$, which are along the cross section or the axis of the tube respectively. We show that the stable tubular bound states of ($nF_s$, $m$D0, D2) which are prevented form collapse by the angular momentum, as original found in flat space, could be formed in the NS5-brane, D6-brane and macroscopic strings background. However, they becomes unstable in the D2-brane and D4-brane background. We also show that there are stable tubular bound states of ($nF_c$, $m$D0, D2) and ($m$D0, D2), which are prevented form collapse by the gravitational forces in the backgrounds of D6-brane. We discuss the properties of these tubular solutions and see that only that in the macroscopic strings background is a supersymmetric BPS configuration.

hep-th↗

arXiv2005

Tubular Solutions of Dirac-Born-Infeld Action on Dp-Brane Background

We use the Dirac-Born-Infeld action on Dp-brane background to find the tubular bound state of a D2 with $m$ D0-branes and $n$ fundamental strings. The fundamental strings may be the circular strings along the cross section of tube or the straight strings along the axial of the tube, and tube solutions are parallel to the geometry of Dp-brane background. Through the detailed analyses we show that only on the D6-brane background could we find the stable tubular solutions. These tubular configurations are prevented form collapse by the gravitational field on the curved Dp-brane background.

hep-th↗