共查询到20条相似文献,搜索用时 171 毫秒
1.
We consider effective actions of the cosmological Friedmann–Robertson–Walker (FRW) models and discuss their fermionic rigid BRST invariance. Further, we demonstrate the finite field-dependent BRST transformations as a limiting case of continuous field-dependent BRST transformations described in terms of continuous parameter κ. The Jacobian under such finite field-dependent BRST transformations is computed explicitly, which amounts an extra piece in the effective action within functional integral. We show that for a particular choice of a parameter the finite field-dependent BRST transformation maps the generating functional for FRW models from one gauge to another. 相似文献
2.
V.A. Novikov M.A. Shifman A.I. Vainshtein V.B. Voloshin V.I. Zakharov 《Nuclear Physics B》1983,229(2):394-406
Instantons in the simplest supersymmetric Yang-Mills theory are considered. We introduce bosonic and fermionic collective coordinates and study how they change under the supersymmetry transformations. The instanton measure is shown to be explicitly invariant under the transformations. We discuss the relation between quantum anomalies and the functional form of the instanton measure. 相似文献
3.
In this paper, two transformations are introduced to solve
sinh-Gordon equation by using the knowledge of elliptic equation
and Jacobian elliptic functions. It is shown that different
transformations are required in order to obtain more kinds of
solutions to the sinh-Gordon equation. 相似文献
4.
In this paper, four transformations are introduced to solve single sine-Gordon equation by using the knowledge of elliptic equation and Jacobian elliptic functions. It is shown that different transformations are required in order to obtain more kinds of solutions to the single sine-Gordon equation. 相似文献
5.
FUZun-Tao YAOZhen-Hua LIUShi-Kuo LIUShi-Da 《理论物理通讯》2005,44(1):23-30
In this paper, four transformations are introduced to solve single sine-Gordon equation by using the knowledge of elliptic equation and Jacobian elliptic functions. It is shown that different transformations are required in order to obtain more kinds of solutions to the single sine-Gordon equation. 相似文献
6.
Sumit Kumar Rai Bhabani Prasad Mandal 《International Journal of Theoretical Physics》2013,52(10):3512-3521
We consider the finite field dependent BRST (FFBRST) transformations in the context of Hamiltonian formulation using Batalin-Fradkin-Vilkovisky method. The non-trivial Jacobian of such transformations is calculated in extended phase space. The contribution from Jacobian can be written as exponential of some local functional of fields which can be added to the effective Hamiltonian of the system. Thus, FFBRST in Hamiltonian formulation with extended phase space also connects different effective theories. We establish this result with the help of two explicit examples. We also show that the FFBRST transformations is similar to the canonical transformations in the sector of Lagrange multiplier and its corresponding momenta. 相似文献
7.
Field redefinitions are considered as a special case of BRST gauge fixings of more general field-enlarging transformations. At the two-loop level an extra local term in the action, the Gervais-Jevicki potential, is generated by point canonical transformations in the bosonic part of the theory. We give an example of how this additional term can be cancelled by the inclusion of the ghost fields. This is achieved through an anomalous Jacobian factor from the ghost measure. 相似文献
8.
M. Lagraa 《Zeitschrift fur Physik C Particles and Fields》1993,57(3):397-401
Calculation of the super Jacobian of the holomorphic Becchi-Rouet-Stora-Tyutin (BRST) transformations of the path-integral functional measure of the spinning string variable and its ghosts in presence of background fields is undertaken in order to obtain BRST current identity and related anomalies. The free BRST current identity is obtained only if the background fields satisfy the equations of motion. In this case the superconformal factor decouples from the background fields and it is possible to incorporate the super Liouville action. 相似文献
9.
The change in the fermionic functional integral measure under chiral rotations is analyzed. Using the ζ-function method, the evaluation of chiral Jacobians to theories including nonhermitian Dirac operators D, can be extended in a natural way. (This being of interest, for example, in connection with the Weinberg-Salam model or with the relativistic string theory.) Results are compared with those obtained following other approaches, the possible discrepancies are analyzed and the equivalence of the different methods under certain conditions on D is proved. Also shown is how to compute the Jacobian for the case of a finite chiral transformation and this result is used to develop a sort of path-integral version of bosonization in d = 2 space-time dimensions. This result is used to solve in a very simple and economical way relevant d = 2 fermionic models. Furthermore, some interesting features in connection with the θ-vacuum in d = 2,4 gauge theories are discussed. 相似文献
10.
M Daoud 《Reports on Mathematical Physics》2003,52(2):281-294
Using the coherent states of many fermionic degrees of freedom labelled by Grassmann variables, we introduce the noncommutative (precisely non-anticommutative) Grassmann star product. The covariance of this star product under unitary transformations, particularly the canonical ones, is studied. The super star product, based on supercoherent states of supersymmetric harmonic oscillator, is also considered. 相似文献
11.
Sudhaker Upadhyay Biswajit Paul 《The European Physical Journal C - Particles and Fields》2016,76(7):394
The Einstein–Hilbert action in the context of higher derivative theories is considered for finding their BRST symmetries. Being a constraint system, the model is transformed in the minisuperspace language with the FRLW background and the gauge symmetries are explored. Exploiting the first order formalism developed by Banerjee et al. the diffeomorphism symmetry is extracted. From the general form of the gauge transformations of the field, the analogous BRST transformations are calculated. The effective Lagrangian is constructed by considering two gauge-fixing conditions. Further, the BRST (conserved) charge is computed, which plays an important role in defining the physical states from the total Hilbert space of states. The finite field-dependent BRST formulation is also studied in this context where the Jacobian for the functional measure is illustrated specifically. 相似文献
12.
Jouko Mickelsson 《Communications in Mathematical Physics》1990,127(2):285-294
We show that the anomalous finite gauge transformations can be realized as linear operators acting on sections of the bundle of fermionic Fock spaces parametrized by vector potentials, and more generally, by splittings of the fermionic one-particle space into a pair of complementary subspaces. On the Lie algebra level we show that the construction leads to the standard formula for the relevant commutator anomalies. 相似文献
13.
We determine the group of implementable local gauge transformations of massless quantum electrodynamics in two space-time dimensions in the covariant Landau gauge. It splits into an infinite discrete set of disjoint classes. The unitary operators representing the implementable gauge transformations are constructed explicitly. A subset of these operators does not reduce to multiples of the identity in the physical Hilbert space constructed according to the usual rules. The disappearance of the fermionic degrees of freedom is related to this fact. Combined with the properties of the global chiral transformations, it provides a better understanding of the model's vacuum structure. 相似文献
14.
We have observed condensation of fermionic atom pairs in the BCS-BEC crossover regime. A trapped gas of fermionic 40K atoms is evaporatively cooled to quantum degeneracy and then a magnetic-field Feshbach resonance is used to control the atom-atom interactions. The location of this resonance is precisely determined from low-density measurements of molecule dissociation. In order to search for condensation on either side of the resonance, we introduce a technique that pairwise projects fermionic atoms onto molecules; this enables us to measure the momentum distribution of fermionic atom pairs. The transition to condensation of fermionic atom pairs is mapped out as a function of the initial atom gas temperature T compared to the Fermi temperature T(F) for magnetic-field detunings on both the BCS and BEC sides of the resonance. 相似文献
15.
C.P. Heidbrink G.S. Uhrig 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(4):443-459
A renormalization scheme for interacting fermionic systems is presented where the renormalization is carried out in terms
of the fermionic degrees of freedom. The scheme is based on continuous unitary transformations of the Hamiltonian which stays
hermitian throughout the renormalization flow, whereby any frequency dependence is avoided. The approach is illustrated in
detail for a model of spinless fermions with nearest neighbour repulsion in one dimension. Even though the fermionic degrees
of freedom do not provide an easy starting point in one dimension favorable results are obtained which agree well with the
exact findings based on Bethe ansatz.
Received 21 August 2002 / Received in final form 29 October 2002 Published online 31 December 2002 相似文献
16.
We measure excitation spectra of an ultracold gas of fermionic (40)K atoms in the BCS-Bose-Einstein-condensation (BEC) crossover regime. The measurements are performed with a novel spectroscopy that employs a small modulation of the B field close to a Feshbach resonance to give rise to a modulation of the interaction strength. With this method we observe both a collective excitation as well as the dissociation of fermionic atom pairs in the strongly interacting regime. The excitation spectra reveal the binding energy or excitation gap for pairs in the crossover region. 相似文献
17.
H. Banerjee G. Bhattacharya R. Banerjee 《Zeitschrift fur Physik C Particles and Fields》1989,45(2):253-260
Gauge theory ofSU(2) Weyl fermions was alleged by Witten to be inconsistent due to global anomaly. Evidences of inconsistency were also reported from contradictions between the anomalousU(1) symmetry and the fact that theSU(2) group is free of local anomaly. Here we show how the zero modes of Dirac operator, ignored by the authors of these arguments, play a decisive role and saveSU(2) Weyl fermions from inconsistency in each case. The symmetric chiral current, obtained by adding the Chern-Simons current to the fermionic chiral current, fails to be conserved precisely due to the contributions of zero modes to the ABJ anomaly equation. The Jacobian of the fermion measure under rigid chiralU(1) transformation is, however, guaranteed to be trivial by the Atiyah-Singer index theorem. Finally, a zero mode is the point of bifurcation of eigenvalue trajectory in the homotopy space. In its neighbourhood the hypothesis of adiabaticity made by Witten breaks down due to violent oscillations between levels, which makes his allegation of global anomaly untenable. 相似文献
18.
In this paper, we will incorporate the generalized uncertainty principle into field theories with Lifshitz scaling. We will first construct both bosonic and fermionic theories with Lifshitz scaling based on generalized uncertainty principle. After that we will incorporate the generalized uncertainty principle into a non-abelian gauge theory with Lifshitz scaling. We will observe that even though the action for this theory is non-local, it is invariant under local gauge transformations. We will also perform the stochastic quantization of this Lifshitz fermionic theory based generalized uncertainty principle. 相似文献
19.
M. Tahiri 《International Journal of Theoretical Physics》1996,35(8):1557-1569
Enlarging the gauge group with two extra fermionic coordinates, we provide a unified geometric formulation of the BRST and
anti-BRST transformations for gravity in the vierbein formalism and simple supergravity. 相似文献
20.
This paper proposes a fermionic linear optical scheme
for the teleportation and entanglement concentration via
entanglement swapping based on charge detection. It also proves that
this method is useful in generating entangled states such as GHZ
states, W states, and cluster states by using fermionic polarizing
beam splitters and single spin rotations assisted by a parity check on
the fermionic qubits. This scheme is nearly deterministic (i.e.,
with 100\% successful probability) and does not need the joint
Bell state measurement required in the previous schemes. 相似文献