From 11366cce7315d0eb75399e517cf8d2976b4cf60d Mon Sep 17 00:00:00 2001
From: Thibaut Lacroix <57836508+tfmlaX@users.noreply.github.com>
Date: Tue, 9 Jul 2024 16:14:37 +0200
Subject: [PATCH] Update findchainlength and add a new method

---
 src/fundamentals.jl | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/fundamentals.jl b/src/fundamentals.jl
index bf82bc6..1dc6dd2 100644
--- a/src/fundamentals.jl
+++ b/src/fundamentals.jl
@@ -339,14 +339,14 @@ end
 
 
 """
-    findchainlength(T, cparams; eps=10^-6, verbose=false)
+    findchainlength(T, cparams::Vector; eps=10^-6, verbose=false)
 
 Estimate length of chain required for a particular set of chain parameters by calculating how long an excitation on the
 first site takes to reach the end. The chain length is given as the length required for the excitation to have just
 reached the last site after time T. The initial number of sites in cparams has to be larger than the findchainlength result.
 
 """
-function findchainlength(T, cparams; eps=10^-4, verbose=false)
+function findchainlength(T, cparams::Vector; eps=10^-4, verbose=false)
     Nmax = length(cparams[1])
     occprev = endsiteocc(T, [cparams[1][1:Nmax], cparams[2][1:Nmax-1]])
     occ = endsiteocc(T, [cparams[1][1:Nmax-1], cparams[2][1:Nmax-2]])
@@ -368,6 +368,20 @@ function findchainlength(T, cparams; eps=10^-4, verbose=false)
     end
 end
 
+"""
+    findchainlength(T, ωc::Float64, β=Inf)
+
+Estimate length of chain using universal asymptotic properties of chain mapped environments given the simulation time T, the bath cut-off frequency ωc, and the inverse temperature β.
+"""
+function findchainlength(T, ωc::Float64, β=Inf)
+    if β==Inf
+        N = ceil(0.25*ωc*T + 0.5)
+    else
+        N = ceil(0.5*ωc*T + 0.5)
+    end
+    return N
+end
+
 """
     chainprop(t, cparams)