Spontaneous Symmetry Breaking in (1+1)-Dimensional Light-Front φ⁴ Theory

抄録

Spontaneous symmetry breaking in (1+1)-dimensional φ⁴ theory is studied with discretized light-front quantization. To compute the critical coupling we calculate the vacuum expectation value of a zero mode through the commutation relations [a₀,a_n] in the Tamm–Dancoff-like approximation. We also estimate effects of non-diagonal interactions to the critical coupling. Our result of the critical coupling is λ_cr=28.0μ²⁄h, which is consistent with the equal-time result 22μ²⁄h≤λ_cr≤55.5μ²⁄h.