# Crossing the c=1 barrier in 2d Lorentzian quantum gravity

@article{Ambjorn1999CrossingTC, title={Crossing the c=1 barrier in 2d Lorentzian quantum gravity}, author={Jan Ambjorn and Konstantinos Anagnostopoulos and R Loll}, journal={Acta Crystallographica Section E-structure Reports Online}, year={1999} }

In an extension of earlier work we investigate the behaviour of two-dimensional Lorentzian quantum gravity under coupling to a conformal field theory with c > 1. This is done by analyzing numerically a system of eight Ising models (corresponding to c=4) coupled to dynamically triangulated Lorentzian ge- ometries. It is known that a single Ising model couples weakly to Lorentzian quantum gravity, in the sense that the Hausdorff dimension of the ensemble of two-geometries is two (as in pure…

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## References

SHOWING 1-10 OF 18 REFERENCES

### Non-perturbative 3d Lorentzian quantum gravity

- Physics
- 2001

The phase structure of the Wick-rotated path integral in three dimensions with the aid of computer simulations is investigated, finding a whole range of the gravitational coupling constant k{sub 0} for which the functional integral is dominated by nondegenerate three-dimensional space-times.

### The Ising Model on a Quenched Ensemble of c=−5 Gravity Graphs

- Physics
- 1999

We study with Monte Carlo methods an ensemble of c=−5 gravity graphs, generated by coupling a conformal field theory with central charge c=−5 to two-dimensional quantum gravity. We measure the…

### A new perspective on matter coupling in two-dimensional gravity.

- Physics
- 1999

We provide compelling evidence that a previously introduced model of non-perturbative 2d Lorentzian quantum gravity exhibits (two-dimensional) flat-space behaviour when coupled to Ising spins. The…

### a Solvable 2d Gravity Model with γ>0

- Physics
- 1994

We consider a model of discretized 2D gravity interacting with Ising spins where the phase boundaries are restricted to have minimal length and show analytically that the critical exponent, γ, is 1/3…