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We consider field theories that exhibit a supersymmetric Lifshitz scaling with two real supercharges. The theories can be formulated in the language of stochastic quantization. We construct the free field supersymmetry algebra with rotation singlet fermions for an even dynamical exponent $z=2k$ in an arbitrary dimension. We analyze the classical and quantum $z=2$ supersymmetric interactions in $2+1$ and $3+1$ spacetime dimensions and reveal a supersymmetry preserving quantum diagrammatic cancellation. Stochastic quantization indicates that Lifshitz scale invariance is broken in the $(3+1)$-dimensional quantum theory., 26 pages

We present a Lorentz-breaking supersymmetric algebra characterized by a critical exponent $z$. Such construction requires a non trivial modification of the supercharges and superderivatives. The improvement of renormalizability for supersymmetric scalar QED is shown and the K\"ahlerian effective potentials are calculated in different cases. We also show how the theory flows naturally to the Lorentz symmetric case at low energies., Comment: 19 pages, 7 figures. Minor correction. Version to appear in PRD

We study how charges of global symmetries that are manifest in the ultra-violet definition of a theory are realized as topological charges in its infra-red effective theory for two-dimensional theories with $\mathcal{N}=(2,2)$ supersymmetry. We focus on the charges that the states living on $S^1$ carry. The central charge---or BPS masses---of the supersymmetry algebra play a crucial role in making this correspondence precise. We study two examples: $U(1)$ gauge theories with chiral matter, and world-volume theories of "dynamical surface operators" of 4d $\mathcal{N}=2$ gauge theories. In the former example, we show that the flavor charges of the theory are realized as topological winding numbers in the effective theory on the Coulomb branch. In the latter, we show that there is a one-to-one correspondence between topological charges of the effective theory of the dynamical surface operator and the electric, magnetic, and flavor charges of the 4d gauge theory. We also examine the topologically charged massive BPS states on $S^1$ and discover that the massive BPS spectrum is sensitive to the radius of the circle in the simplest theory---the free theory of a periodic twisted chiral field. We clarify this behavior by showing that the massive BPS spectrum on $S^1$, unlike the BPS ground states, cannot be identified as elements of a cohomology.

We consider $$ \mathcal{N}=2 $$ supersymmetric gauge theories on four manifolds admitting an isometry. Generalized Killing spinor equations are derived from the consistency of supersymmetry algebrae and solved in the case of four manifolds admitting a U(1) isometry. This is used to explicitly compute the supersymmetric path integral on S2 × S2 via equivariant localization. The building blocks of the resulting partition function are shown to contain the three point functions and the conformal blocks of Liouville Gravity.

A coset model based on the hyperbolic Kac–Moody algebra E10 has been conjectured to underly eleven-dimensional supergravity and M theory. In this note we study the canonical structure of the bosonic model for finite- and infinite-dimensional groups. In the case of finite-dimensional groups like GL(n) we exhibit a convenient set of variables with Borel-type canonical brackets. The generalisation to the Kac–Moody case requires a proper treatment of the imaginary roots that remains elusive. As a second result, we show that the supersymmetry constraint of D = 11 supergravity can be rewritten in a suggestive way using E10 algebra data. Combined with the canonical structure, this rewriting explains the previously observed association of the canonical constraints with null roots of E10. We also exhibit a basic incompatibility between local supersymmetry and the K(E10) ‘R symmetry’, that can be traced back to the presence of imaginary roots and to the unfaithfulness of the spinor representations occurring in the present formulation of the E10 worldline model, and that may require a novel type of bosonisation/fermionisation for its resolution. This appears to be a key challenge for future progress with E10.

We study ten-dimensional supersymmetric vacua with NSNS non-geometric fluxes, in the framework of $\beta$-supergravity. We first provide expressions for the fermionic supersymmetry variations. Specifying a compactification ansatz to four dimensions, we deduce internal Killing spinor equations. These supersymmetry conditions are then reformulated in terms of pure spinors, similarly to standard supergravity vacua admitting an SU(3)xSU(3) structure in Generalized Complex Geometry. The standard d-H acting on the pure spinors is traded for a generalized Dirac operator D, depending here on the non-geometric fluxes. Rewriting it with an exponential of the bivector $\beta$ leads us to discuss the geometrical characterisation of the vacua in terms of a $\beta$-twist, in analogy to the standard twist by the b-field. Thanks to D, we also propose a general expression for the superpotential to be obtained from standard supergravities or $\beta$-supergravity, and verify its agreement with formulas of the literature. We finally comment on the Ramond-Ramond sector, and discuss a possible relation to intermediate or dynamical SU(2) structure solutions., Comment: 25 pages + appendices and references; v2: minor changes, published version

In this paper, we will analyze three-dimensional supersymmetric Yang-Mills theory coupled to matter fields in $SIM(1)$ superspace formalism. The original theory which is invariant under the full Lorentz group has $\mathcal{N}=1$ supersymmetry. However, when we break the Lorentz symmetry down to $SIM(1)$ group, the $SIM(1)$ superspace will break half the supersymmetry of the original theory. Thus, the resultant theory in $SIM(1)$ superspace will have $\mathcal{N}=1/2$ supersymmetry. This is the first time that $\mathcal{N}=1$ supersymmetry will be broken down to $\mathcal{N}=1/2$ supersymmetry, for a three-dimensional theory, on a manifold without a boundary. This is because it is not possible to use nonanticommutativity to break $\mathcal{N}=1$ supersymmetry down to $\mathcal{N}=1/2$ supersymmetry in three dimensions.

The paper presents the bosonic and fermionic supersymmetric extensions of the structural equations describing conformally parametrized surfaces immersed in a Grasmann superspace, based on the authors' earlier results. A detailed analysis of the symmetry pro- perties of both the classical and supersymmetric versions of the Gauss{Weingarten equations is performed. A supersymmetric generalization of the conjecture establishing the necessary conditions for a system to be integrable in the sense of soliton theory is formulated and illustrated by the examples of supersymmetric versions of the sine-Gordon equation and the Gauss{Codazzi equations.

This chapter describes how the method of twisted supersymmetric fields used for describing global supersymmetry, as in the context of topological field theories, can be extended to the description of local supersymmetry. As an example, the method is applied to the case of N = 1 Euclidean supergravity on a 4-manifold with an almost complex structure, with its couplings to scalar and vector multiplets.

Soft limits of a massless S matrix are known to reflect the symmetries of the theory. In particular, for theories with Goldstone bosons, the double-soft limit of scalars reveals the coset structure of the vacuum manifold. In this Letter, we propose that such universal double-soft behavior is not only true for scalars, but also for spin-1/2 particles in four dimensions and fermions in three dimensions. We first consider the Akulov-Volkov theory and demonstrate that the double-soft limit of Goldstinos yields the supersymmetry algebra. More surprisingly, we also find that amplitudes in 4≤N≤8 supergravity theories in four dimensions as well as N=16 supergravity in three dimensions behave universally in the double-soft-fermion limit, analogous to the scalar ones. The validity of the new soft theorems at loop level is also studied. The results for supergravity are beyond what is implied by supersymmetry Ward identities and may impose nontrivial constraints on the possible counterterms for supergravity theories.

We formalize higher-dimensional and higher gauge WZW-type sigma-model local prequantum field theory, and discuss its rationalized/perturbative description in (super-)Lie n-algebra homotopy theory (the true home of the "FDA"-language used in the supergravity literature). We show generally how the intersection laws for such higher WZW-type σ-model branes (open brane ending on background brane) are encoded precisely in (super-)L∞-extension theory and how the resulting "extended (super-)space-times" formalize spacetimes containing σ-model brane condensates. As an application we prove in Lie n-algebra homotopy theory that the complete super-p-brane spectrum of superstring/M-theory is realized this way, including the pure σ-model branes (the "old brane scan") but also the branes with tensor multiplet worldvolume fields, notably the D-branes and the M5-brane. For instance the degree-0 piece of the higher symmetry algebra of 11-dimensional (11D) spacetime with an M2-brane condensate turns out to be the "M-theory super-Lie algebra". We also observe that in this formulation there is a simple formal proof of the fact that type IIA spacetime with a D0-brane condensate is the 11D sugra/M-theory spacetime, and of (prequantum) S-duality for type IIB string theory. Finally we give the non-perturbative description of all this by higher WZW-type σ-models on higher super-orbispaces with higher WZW terms in stacky differential cohomology.

Yüksek Lisans Tezi Bu tezin amacı bir boyutlu süpersimetrik kuantum mekaniğine giriş sağlamaktır. Süpersimetrik kuantum mekaniğinin Hamiltonyen formülasyonu kurulduktan sonra çözülebilir bir Hamiltonyenden başlayarak aynı spektruma sahip yeni Hamiltonyenler kurma yöntemi basit örnekle açıklanmıştır. Pöschl-Teller I ve Morse potansiyelleri için enerji spektrumunun analitik ifadesi süpersimetri ve şekil değişmezlik koşulundan elde edilmiştir. abstract This master thesis is intended to provide an introduction to supersymmetric quantum mechanics ( SUSY Q.M ) in one dimension. After setting up a Hamiltonian formulation of SUSY Q.M , we illustrate its powerful techninque for designing Hamiltonians with a prescribed energy spectrum from known exactly solvable one . For Pöschl-Teller I and Mors potentials , analytic expressions for the energy spectrum are derived using SUSY and the shape invariant condition.

This review is devoted to highlight some aspects of the relevance of Majorana fermions in rigid supersymmetry breaking in four spacetime dimensions. After introducing some basic facts on spinors, and on their symmetries and reality properties, we consider Goldstino actions describing partial breaking of rigid supersymmetry, then focussing on Born-Infeld non-linear theory, its duality symmetry, and its supersymmetric extensions, also including multi-field generalizations exhibiting doubly self-duality., Comment: 1+27 pages, 1 Table. Contribution to the Proceedings of the Erice International School of Subnuclear Physics, 53rd Course : "The Future of Our Physics Including New Frontiers", and Celebration of the Triumph of Ettore Majorana, Erice, 24 June-3 July 2015. Dedicated to the memory of Guido Altarelli

In this note, we introduce the generalization of opers (superopers) for a certain class of superalgebras, which have pure odd simple root system. We study in detail $SPL_2$-superopers and in particular derive the corresponding Bethe ansatz equations, which describe the spectrum of $osp(2|1)$ Gaudin model., 21 pages, v2: minor corrections

We provide the classification of real forms of complex D=4 Euclidean algebra $\mathcal{\epsilon}(4; \mathbb{C}) = \mathfrak{o}(4;\mathbb{C})) \ltimes \mathbf{T}_{\mathbb{C}}^4$ as well as (pseudo)real forms of complex D=4 Euclidean superalgebras $\mathcal{\epsilon}(4|N; \mathbb{C})$ for N=1,2. Further we present our results: N=1 and N=2 supersymmetric D=4 Poincare and Euclidean r-matrices obtained by using D= 4 Poincare r-matrices provided by Zakrzewski [1]. For N=2 we shall consider the general superalgebras with two central charges., Comment: 20 pages, presented at XXIII-th International Conference on Integrable Systems and Quantum Symmetries, Prague, June 2015; to be published in JPhysA Conference Series, ed. C. Burdik, S.Posta and O.Navratil

We construct, for any given ${\ell}=\frac{1}{2}+{\mathbb{N}}_0$, the second-order, linear PDEs which are invariant under the centrally extended Conformal Galilei Algebra. \par At the given ${\ell}$, two invariant equations in one time and ${\ell}+\frac{1}{2}$ space coordinates are obtained. The first equation possesses a continuum spectrum and generalizes the free Schr\"odinger equation (recovered for ${\ell}=\frac{1}{2}$) in $1+1$ dimension. The second equation (the "$\ell$-oscillator") possesses a discrete, positive spectrum. It generalizes the $1+1$-dimensional harmonic oscillator (recovered for $\ell=\frac{1}{2}$). The spectrum of the ${\ell}$-oscillator, derived from a specific $osp(1|2\ell+1)$ h.w.r., is explicitly presented.\par The two sets of invariant PDEs are determined by imposing (representation-dependent) {\it on-shell invariant conditions} both for {\it degree} $1$ operators (those with continuum spectrum) and for {\it degree } $0$ operators (those with discrete spectrum).\par The on-shell condition is better understood by enlarging the Conformal Galilei Algebras with the addition of certain second-order differential operators. Two compatible structures (the algebra/superalgebra duality) are defined for the enlarged set of operators., Comment: 18 pages

D-branes have a world-volume U(1) gauge field A whose field strength F = dA gives rise to a Born-Infeld term in the D-brane action. Supersymmetry and kappa symmetry transformations of A are traditionally inferred by the requirement that the Born-Infeld term is consistent with both supersymmetry and kappa symmetry of the D-brane action. In this paper, we show that integrability of the assigned supersymmetry transformations leads to a extension of the standard supersymmetry algebra that includes a fermionic central charge. We construct a superspace one-form on an enlarged superspace related by a coset construction to this centrally extended algebra whose supersymmetry and kappa symmetry transformations are derived, rather than inferred. It is shown that under pullback, these transformations are of the form expected for the D-brane U(1) gauge field. We relate these results to manifestly supersymmetric approaches to construction of D-brane actions., Comment: 15 pages; new section and references added

The super-algebraic structure of a generalized version of the Jaynes–Cummings model is investigated. We find that a Z2 graded extension of the so(2,1) Lie algebra is the underlying symmetry of this model. It is isomorphic to the four-dimensional super-algebra u(1/1) with two odd and two even elements. Differential matrix operators are taken as realization of the elements of the superalgebra to which the model Hamiltonian belongs. Several examples with various choices of superpotentials are presented. The energy spectrum and corresponding wavefunctions are obtained analytically.

Dimensional reduction of the D = 2 minimal super-Yang–Mills to the D = 1 matrix quantum mechanics is shown to double the number of dynamical supersymmetries, from N = 1 to N = 2 . We analyze the most general supersymmetric deformations of the latter, in order to construct the noncritical 3D M -theory matrix model on generic supersymmetric backgrounds. It amounts to adding quadratic and linear potentials with arbitrary time-dependent coefficients, namely, a cosmological ‘constant’, Λ ( t ) , and an electric flux background, ρ ( t ) , respectively. The resulting matrix model enjoys, irrespective of Λ ( t ) and ρ ( t ) , two dynamical supersymmetries which further reveal three hidden so ( 1 , 2 ) symmetries. All together they form the supersymmetry algebra, osp ( 1 | 2 , R ) . Each so ( 1 , 2 ) multiplet in the Hilbert space visualizes a dynamics constrained on either Euclidean or Minkowskian dS 2 / AdS 2 space, depending on its Casimir. In particular, all the unitary multiplets have the Euclidean dS 2 / AdS 2 geometry. We conjecture that the matrix model provides holographic duals to the 2D superstring theories on various backgrounds having the spacetime signature Minkowskian if Λ ( t ) > 0 , or Euclidean if Λ ( t ) 0 .

The dynamical (super)symmetries for various monopole systems are reviewed. For a Dirac monopole, no smooth Runge-Lenz vector can exist; there is, however, a spectrum-generating conformal $o(2,1)$ dynamical symmetry that extends into $osp(1/1)$ or $osp(1/2)$ for spin 1/2 particles. Self-dual 't Hooft-Polyakov-type monopoles admit an $su(2/2)$ dynamical supersymmetry algebra, which allows us to reduce the fluctuation equation to the spin zero case. For large $r$ the system reduces to a Dirac monopole plus an suitable inverse-square potential considered before by McIntosh and Cisneros, and by Zwanziger in the spin 0 case, and to the `dyon' of D'Hoker and Vinet for spin 1/2. The asymptotic system admits a Kepler-type dynamical symmetry as well as a `helicity-supersymmetry' analogous to the one Biedenharn found in the relativistic Kepler problem. Similar results hold for the Kaluza-Klein monopole of Gross-Perry-Sorkin. For the magnetic vortex, the N=2 supersymmetry of the Pauli Hamiltonian in a static magnetic field in the plane combines with the $o(2)\times o(2,1)$ bosonic symmetry into an $o(2)\times osp(1/2)$ dynamical superalgebra., Minor corrections.18 pages, no figures. Based on a review talk given at the International Symposium on Advanced Topics in Quantum Physics, Shanxi'92. Ed. J.-Q. Liang, M.-L. Wang, S.-N. Qiao, D.C. Su. pp. 283- 293. Science Press, Beijing (1993) [Tours Preprint N. 47/92], and on Tours Preprint N. 60/93 (1993) (unpublished)

After reviewing the oscillator realization of the symmetry superalgebra of the BMN matrix model on its maximally supersymmetric plane-wave background and the construction of its zero-mode spectrum, we study a large number of non-maximally supersymmetric pp-wave algebras in eleven dimensions which are obtained by various restrictions from the maximally supersymmetric case (BMN model). We also show how to obtain their zero-mode spectra, which we explicitly construct in some chosen examples. Except for some `exotic' or degenerate special cases, we believe our study covers all possible interesting pp-wave superalgebras of this kind in eleven dimensions., Comment: 48 pages; latex file

We give the classification of the positive energy (lowest weight) unitary irreducible representations of the superalgebras osp(1|2n,R)., Comment: 20 pages, LATEX2e (revtex4,amsmath,amssymb), Plenary talk by VKD at X International Conference on Symmetry Methods in Physics, Yerevan, 13-21.8.2003; added acknowledgements; corrected misprints

We show that the 4-dimensional N = 1 / 2 supersymmetry algebra admits central extension. The central charges are supported by a domain wall and the central charges are computed. We also determine the Konishi anomaly for N = 1 / 2 supersymmetric gauge theory. Due to the new couplings in the Lagrangian, many terms appear. We show that these terms sum up to give the expected form for the holomorphic part of the Konishi anomaly. For the antiholomorphic part, we give a simple argument that the naive generalization has to be modified. We suggest that the antiholomorphic Konishi anomaly is given by a gauge invariant completion using the open Wilson line.

The underlying gauge group structure of the D=11 Cremmer-Julia-Scherk supergravity becomes manifest when its three-form field A_3 is expressed through a set of one-form gauge fields. These are associated with the generators of the elements of a family of enlarged supersymmetry algebras $\tilde{\mathfrak{E}}^{(528|32+32)}(s)$ parametrized by a real number s. We study in detail the composite structure of A_3 extending previous results by D'Auria and Fr\'e, stress the equivalence of the above problem to the trivialization of a standard supersymmetry algebra ${\mathfrak{E}}^{(11|32)}$ cohomology four-cocycle on the enlarged ${\tilde {\mathfrak{E}}}^{(528|32+32)}(s)$ superalgebras, and discuss its possible dynamical consequences. To this aim we consider the properties of the first order supergravity action with a composite A_3 field and find the set of extra gauge symmetries that guarantee that the field theoretical degrees of freedom of the theory remain the same as with a fundamental A_3. The extra gauge symmetries are also present in the so-called rheonomic treatment of the first order D=11 supergravity action when A_3 is composite. Our considerations on the composite structure of A_3 provide one more application of the idea that there exists an extended superspace coordinates/fields correspondence. They also suggest that there is a possible embedding of D=11 supergravity into a theory defined on the enlarged superspace ${\tilde{\Sigma}}^{(528|32+32)}(s)$., Comment: Two references added, a numerical factor corrected, as published in Ann. Phys

Using the analytical transfer matrix method in combination of supersymmetry algebra, we have analytically derived the eigenenergies of the Morse potential. The derived eigenenergies are, of course, identical with previously known values. The analytical transfer matrix method is found to be exact and useful for understanding the nature of bound states. And the highest bound state possible in the Morse potential is mathematically determined without ambiguity.

We study the Hamiltonian structure and constraints of twistor-like super p-brane which preserves 3/4 of D = 4, N = 1 supersymmetry using the conversion method. Classical and quantum realizations of the BRST charge, the unified superalgebra of symmetries of the p-brane action, including generalized global superconformal OSp (1|8) symmetry together with Virasoro and Weyl symmetries, are presented. We prove nilpotency of the Hermitian quantum BRST charge of the p-brane and closure of the quantized superalgebra OSp (1|8) of its global symmetry.

A string in four dimensions is constructed by supplementing it with 44 Majorana fermions. The later are represented by 11 vectors in the bosonic representation SO (D-1,1). The central charge is 26. The fermions are grouped in such a way that the resulting action is worldsheet supersymmetric. The energy–momentum and current generators satisfy the super-Virasoro algebra. GSO projections are necessary for proving modular invariance. Space–time supersymmetry algebra is deduced and is substantiated for specific modes of zero mass. The symmetry group of the model can descend to the low energy standard model group SU (3)× SU L(2)× U Y(1) through the Pati–Salam group.

We give a brief review of supersymmetic pseudo-Hermitian quantum mechanics and its statistical structure. We also elaborate on abnormal pseudo-Hermitian fermions that arise as the ingredients of one of the two basic realizations of pseudo-Hermitian supersymmetry and discuss the associated algebraic structures.

We construct a variety of off-shell N = 8 , d = 1 supermultiplets with finite numbers of component fields as direct sums of properly constrained N = 4 , d = 1 superfields. We also show how these multiplets can be described in N = 8 , d = 1 superspace where the whole amount of supersymmetry is manifest. Some of these multiplets can be obtained by dimensional reduction from N = 2 multiplets in d = 4 , whereas others cannot. We give examples of invariant superfield actions for the multiplets constructed, including N = 8 superconformally invariant ones.

We show that the construction of super-Calogero model with OSp(2|2) supersymmetry is not unique. In particular, we find a new co-ordinate representation of the generators of the OSp(2|2) superalgebra that appears as the dynamical supersymmetry of the rational super-Calogero model. Both the quadratic and the cubic Casimir operators of the OSp(2|2) are necessarily zero in this new representation, while they are, in general, nonzero for the super-Calogero model that is currently studied in the literature. The Scasimir operator that exists in the new co-ordinate representation is not present in the case of the existing super-Calogero model. We also discuss the case of N free superoscillators and superconformal quantum mechanics for which the same conclusions are valid., Revtex4, 20 pages, no figure; Version to appear in Nuclear Physics B

A fully quantum version of the Witten-Olive analysis of the central charge in the N=1 Wess-Zumino model in $d=2$ with a kink solution is presented by using path integrals in superspace. We regulate the Jacobians with heat kernels in superspace, and obtain all superconformal anomalies as one Jacobian factor. The conserved quantum currents differ from the Noether currents by terms proportional to field equations, and these terms contribute to the anomalies. We identify the particular variation of the superfield which produces the central charge current and its anomaly; it is the variation of the auxiliary field. The quantum supersymmetry algebra which includes the contributions of superconformal anomalies is derived by using the Bjorken-Johnson-Low method instead of semi-classical Dirac brackets. We confirm earlier results that the BPS bound remains saturated at the quantum level due to equal anomalies in the energy and central charge., 36 pages

We derive the necessary and sufficient condition for Type A N-fold supersymmetry by direct calculation of the intertwining relation and show the complete equivalence between this analytic construction and the sl(2) construction based on quasi-solvability. An intimate relation between the pair of algebraic Hamiltonians is found. The classification problem on Type A N-fold supersymmetric models is investigated by considering the invariance of both the Hamiltonians and N-fold supercharge under the GL(2,K) transformation. We generalize the Bender-Dunne polynomials to all the Type A N-fold supersymmetric models without requiring the normalizability of the solvable sector. Although there is a case where weak orthogonality of them is not guaranteed, this fact does not cause any difficulty on the generalization. It is shown that the anti-commutator of the Type A N-fold supercharges is expressed as the critical polynomial of them in the original Hamiltonian, from which we establish the complete Type A N-fold superalgebra. A novel interpretation of the critical polynomials in view of polynomial invariants is given., 33 pages, REVTeX4, typos corrected

We derive topological algebras for two-dimensional models admitting a d=[δ,b] decomposition (with b the BRST operator). In general, the topological algebra we obtain is not derived from the twisting of an N=2 supersymmetry algebra. We show, for the particular case of an Abelian model described by a ladder of matter, how to derive N=2 supersymmetry generators from the odd generators of the topological algebra.

We formulate gauge invariant interactions of totally symmetric tensor and tensor-spinor higher spin gauge fields in AdS 5 that properly account for higher-spin-gravitational interactions at the action level in the first non-trivial order.

We study various aspects of N=(4,4) type IIA GS superstring theory in the pp-wave background, which arises as the compactification of maximally supersymmetric eleven-dimensional pp-wave geometry along the spacelike isometry direction. We show the supersymmetry algebra of N=(4,4) worldsheet supersymmetry as well as non-linearly realized supersymmetry. We also give quantization of closed string and open string incorporating various boundary conditions. From the open string boundary conditions, we find configurations of D-branes which preserve half the supersymmetries. Among these we identify D4 brane configurations with longitudinal five brane configurations in matrix model on the eleven-dimensional pp-wave geometry.

The present lecture is a beginer's guide to supersymmetry, superstrings, and M-theory. It addresses students and scientists whose basic research topic in theoretical physics is a different one but who, nonetheless, wish to gain a glimpse into this exciting new field of theoretical physics.

We construct Wigner's continuous spin representations of the Poincar\'e algebra for massless particles in higher dimensions. The states are labeled both by the length of a space-like translation vector and the Dynkin indices of the {\it short little group} $SO(d-3)$, where $d$ is the space-time dimension. Continuous spin representations are in one-to-one correspondence with representations of the short little group. We also demonstrate how combinations of the bosonic and fermionic representations form supermultiplets of the super-Poincar\'e algebra. If the light-cone translations are nilpotent, these representations become finite dimensional, but contain zero or negative norm states, and their supersymmetry algebra contains a central charge in four dimensions., Comment: 19 pages

A pp-wave solution to 11-dimensional supergravity is given with precisely 26 supercharges. Its uniqueness and the absence of 11-dimensional pp-waves which preserve (precisely) 28 or 30 supercharges is discussed. Compactification on a spacelike circle gives a IIA configuration with all 26 of the supercharges. For this compactification, D0 brane charge does not appear in the supersymmetry algebra. Indeed, the 26 supercharge IIA background does not admit any supersymmetric D-branes. In an appendix, a 28 supercharge IIB pp-wave is presented along with its supersymmetry algebra., Comment: 18 pages REVTeX 4 and AMSLaTeX. v3: Equations (III.17) and (III.18) corrected. Reference added. v4: more typos corrected and references added

We study the spectrum of the recently proposed matrix model of DLCQ M-theory in a parallel plane (pp)-wave background. In contrast to matrix theory in a flat background this model contains mass terms, which lift the flat directions of the potential and renders its spectrum discrete. The supersymmetry algebra of the model groups the energy eigenstates into supermultiplets, whose members differ by fixed amounts of energy in great similarity to the representation of supersymmetry in AdS spaces. There is a unique and exact zero-energy groundstate along with a multitude of long and short multiplets of excited states. For large masses the quantum mechanical model may be treated perturbatively and we study the leading order energy shifts of the first excited states up to level two. Most interestingly we uncover a protected short multiplet at level two, whose energies do not receive perturbative corrections. Moreover, we conjecture the existence of an infinite series of similar protected multiplets in the pp-wave matrix model., 18 pages, 2 tables, v2: typos corrected and references added, v3: one reference added

Effect of the supersymmetry enhancement due to the presence of tensor central charge coordinates in the models of tensionless superstring and superbrane is studied. Exactly solvable super p -brane model preserving 3/4 of the D =4, N =1 supersymmetry is presented. The fine tuning of extra κ -symmetry with the R -symmetry is observed. We show that the general solution for the Goldstone fermion is pure static.

Using the idea of shape invariance with respect to the main quantum number n, we represent Lie algebras u(2) and u(1, 1). The induced metric by the Casimir operator of Lie algebras u(2) and u(1, 1) leads us to obtain new solutions of the Dirac equation corresponding to a spin-½ charged particle on the 2D sphere S2 and the hyperbolic plane H2 in the presence of a magnetic monopole. It is shown that the related new spinors represent the supersymmetry algebra, and that they satisfy shape invariance equations with respect to n.

N = 4 superconformal quantum mechanics of nonrelativistic particles in the typical 1/x(2)-potentials, which holds not only supersymmetry but also dynamical conformal symmetry, is studied. The corresponding superconformal quantum mechanical algebra, which contains supersymmetric quantum mechanical algebra With four supercharges and conformal algebra as subalgebras, and its two canonical group chains are established.

The (group and spin space) matrix Hamiltonian describing the dynamics of a non-relativistic spin-½ particle moving in a static, but spatially dependent, non-Abelian magnetic field in two spatial dimensions is shown to take the form of an anticommutator of a nilpotent operator and its Hermitian conjugate. Consequently, the (group space) matrix Hamiltonians for the two different spin projections form partners of a supersymmetric quantum mechanical system. The resulting supersymmetry algebra is exploited to explicitly construct the exact zero energy ground state wave function(s) for the system. The remaining eigenstates and eigenvalues of the two partner Hamiltonians form positive energy degenerate pairs.

The simplest supersymmetry algebra and superspace in three-dimensional Euclidean (3dE) space is examined. Representations of the algebra are considered and the implications of restricting the space of states to states with positive definite norm are determined. A superspace is defined and superfields are introduced. Supersymmetric field theory models in 3dE are described in both superfield and component field forms. The relationship between these models and similar models in four-dimensional Minkowski space is described.

In this work, we expand the hidden AdS-Lorentz superalgebra underlying D=4 supergravity, reaching a (hidden) Maxwell superalgebra. The latter can be viewed as an extension involving cosmological constant of the superalgebra underlying D=4 supergravity in flat spacetime. We write the Maurer-Cartan equations in this context and we find some interesting extensions of the antisymmetric 3-form A(3) appearing in the Free Differential Algebra in Minkowski space. The structure of Free Differential Algebras is obtained by considering the zero curvature equations. We write the parametrization of A(3) in terms of 1-forms and we rend the topological features of its extensions manifest. We interestingly find out that the structure of these extensions, and consequently the structure of the corresponding boundary contribution dA(3), strongly depends on the form of the extra fermionic generator appearing in the hidden Maxwell superalgebra. The model we develop in this work is defined in an enlarged superspace with respect to the ordinary one, and the extra bosonic and fermionic 1-forms required for the closure of the hidden Maxwell superalgebra must be considered as physical fields in this enlarged superspace.

We present a unifying theme relating BPS partition functions and superconformal indices. In the case with complex SUSY central charges (as in N=2 in d=4 and N=(2,2) in d=2) the known results can be reinterpreted as the statement that the BPS partition functions can be used to compute a specialization of the superconformal indices. We argue that in the case with real central charge in the supersymmetry algebra, as in N=1 in d=5 (or the N=2 in d=3), the BPS degeneracy captures the full superconformal index. Furthermore, we argue that refined topological strings, which captures 5d BPS degeneracies of M-theory on CY 3-folds, can be used to compute 5d supersymmetric index including in the sectors with 3d defects for a large class of 5d superconformal theories. Moreover, we provide evidence that distinct Calabi-Yau singularities which are expected to lead to the same SCFT yield the same index., Comment: 58 pages

We give an octonionic formulation of the $$ \mathcal{N}=1 $$ supersymmetry algebra in D = 11, including all brane charges. We write this interms of a novel outer product, which takes a pair of elements of the division algebra $$ \mathbb{A} $$ and returns a real linear operator on $$ \mathbb{A} $$ . More generally, with this product comes the power to rewrite any linear operation on $$ {\mathbb{R}}^n $$ (n =1, 2, 4, 8) in terms of multiplication in the n-dimensional division algebra $$ \mathbb{A} $$ . Finally, we consider the reinterpretation of the D =11 supersymmetry algebra as an octonionic algebra in D =4 and the truncation to division subalgebras.